First off, lets get this party started right..
http://powerhouse.nullware.com/powerhouse.html (Mids lite)
http://web.archive.org/web/20130825235946/http://champions-online-wiki.com/wiki/Power_Sets (Mids Add-on)
http://www.arcgames.com/en/forums/championsonline#/discussion/234470/specialization-tree-info (Mids Add-on)
http://www.arcgames.com/en/forums/championsonline#/discussion/225717/de-buffs-and-debuffs (Mids add-on)
http://www.arcgames.com/en/forums/championsonline#/discussion/175864/faq-for-bindings-commands (keybinds)
http://champions-online.proboards.com/thread/564 (Many builds, some build guides)
You now have the information at your fingertips to build a Champion.
Soooo to the questions...
If you want to play something that's easiest on your hands I can tell you right off that you want to play Ranged. Playing melee destroyed my mouse...! And I had fun doing it. It makes my dogs edgy, too.. I just get too into my melee maybe.
As far as what is survivable... That's playstyle. I have a toon that has 6 Billion Smashes Served (TM) (it's a queue thing) and he usually ends up tanking, and he is dps, has a offense passive, and he has no heal. I have to play him by the seat of my pants.. hehe. Even pre-nerfed... *ahem*
Get used to getting nerfed btw. This usually happens ~ the time you are happy with your build.
Flying is cool if you're into that. Most ranged dps probably are (judging by my loose head count) and flying can make some encounters go from being hard to trivial. There is exponentially less movement involved in flying vs. Athletics. With Athletics I'm all over the place, with Flying I generally go from spot to spot. All of my toons have Athletics at at least level 2 and have the advantage I forget the name of already... The one that makes you go fast when mobs try to make you go slow.I really liked Combat Jumping and whatever that other jumping thing was we got in CoH and Athletics just takes that to the next level for me. One of my first mouse buttons to start going out was the one I used to make barrel rolls.. Teleportation is also very worthy to check out. It has a nice inherent agro wipe and is fast. For combat... nahhh prolly not a good choice. Maybe for a tank going from spot to spot or someone with innate teleportation combat skills. *shrug* You can eventually have two travel powers in case you didn't know yet.
I'm not real big on blocking.. I finally made a build with a fully ranked block right before I took my current break from CO ... And They Nerfed It Right Afterwards.. Having said that, though, blocking is an extreeeeemely effective tool in CO even if you don't take a blocking power. Blocking can be as elegant or simple as you want - you can be real good at knowing when to do it or just know well enough when to do it before you faceplant and hope it can buy you the time you need. Block is very powerful in CO, tho, don't discount it. If your hps start plumetting it's generally a decent time to try it out even if you don't have a Block power.
Rimefire can be very powerful. I played around with this for awhile. It was too gimicky for me. I like nice dependable boom/meltage.
It's hard to go wrong with what powerset to chose and all that good stuff. First off, 99% of the content in CO can be played in a team or solo with any Real powerset. A 'real' powerset is defined as one that you can look at and interpret as a complete powerset. Like Fire, or Might. Over there to the far right where the Celestials are gets more questionable and you probly won't go there anyway due to .. why would you. The Supernaturals and Darkness powersets also live to the far right of your power choice screen and Are complete powersets.
Basically, as it was with CoH when you got good at it, all powersets will do the job it's more a matter of what fits you best playstylewise and looks most fun at thus particular moment.
Having said that... Some decent heals are.. Bountiful Chi Resurgence - with the advantage, virtually always, and with some dodge if at all possible. Another good heal can be Conviction. For some toons the cost can be highish and the recharge time slowish. A good toggle heal is... gah.. whatever the only toggle heal is called.
Toggle powers are a whole other beast by the way. I would recommend avoiding toggle powers, such as you will mostly find in Power Armor, until you're more comfortable with the game. It took me forever to get the hang of them and I'm still not sure I like them.
There is also a lot of passsssive healing. This can be very helpful. There's things that give you hp's on a defeat/crit... per tic..per situation (Sentinal Mastery f/x..) and there are two lifetaps (you damage them and get healed at the same time), one is melee and one is ranged.
When all else fails... check your Mids add-on for ideas..
http://web.archive.org/web/20130808131939/http://champions-online-wiki.com/wiki/HealingThe wiki has many things catagorized nicely for you btw...
It's worth it. Making builds in CO, that is. I think. If you like making builds, it's an artform in CO. Thing is, their best feature is also the thing they like to fidget with most. So, get used to being nerfed. You probly won't feel the pain until a good year or so into the game... hehe
I didn't give you a ton of specifics but I hope the links help and I'll do what I can to make you into a lean, mean, toonin' macheen.
One thing that helps in making a build are looking at builds already made and there are tons in that link above. Some of my tips would be to try and concentrate on the basics in the beginning. What powers do you want to use. What passive looks most attractive - Defense, Offense, Support, Hybrid? What toggle power works for you (damage buff, Concentration for Example). Oh and an energy unlock. Put some thought into that. Active Defenses can be very helpful Oh No buttons - Masterful Dodge and Unbreakable are two of the more useful ones. You might also be interested in agro wipes like Evasive Manuevers w/advantage.
Mostly, it's all about what's fun to you. About annnnnny decently thought out and played build can make it through 99% of the content in the game both solo and in teams, so, concentrate on what looks funnest, I would say. Some people can tear up a powerset that others fumble with. It's not just about the powers but you do want a good foundation of understanding how builds work. So off to the Wiki and Powerhouse with you! *kawhip*! and when you have questions ask away.
Basically, as every, Kaos summed it up in 1/100 the words (while I was writing my book). Just play what looks fun but do figure out the basic mechanics of things like active defenses/offenses, passive defenses, energy unlocks, toggle/buff powers,.. It usually helps to have a heal, so it wouldn't hurt to check out the list above for something that looks decent. Oh and you can res yourself (and/or others) too. There are also circle powers and pets that might interest you but I don't generally use them. Probably one of the most popular healing powers is Support Drones but it sucks too much energy for my taste.
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It's also probably worth mentioning what's been nerfed in gear (that comes to mind atm)...
Don't bother with:
Recharge (until/unless you reeeeally need to squeeze a tiny bit out of your gear)
Crowd control resistance
....what else?