Rag

Or you can tribrid it like how I'm going to do. Getting first aid, damage, evasion, and armor along with items to help out everyone.

Heyo, Level 48 Zelrius here to give in my piece. Refer to this Triangle that I made for questions like this:

http://i.imgur.com/l4Cyhcj.png

As you can see, there are plenty of names for the several different builds, and it is always best to pick a corner and get as close to it as possible, with an addition of a second corner down the line. Whatever you do, avoid the center. Being too Balanced and unspecialized will make you useless in any team situation, including boss fights. If you're too balanced, you'll have a little of everything, but will be terribly out done by the other roles. 

^ Like Zel said you can follow his chart, however if you haven't been in many RPs yet, I'd suggest to feel out your character, because from an RP aspect you'd want your character's build to match.

Ex. Is he the type of hit first and ask questions later, or that the best defense is a good offense? If so then he might edge towards a dps or glass cannon type of build. If he's more oriented toward keeping his teammates safe and shoulder whatever blows come their way, you might want to move towards a more tanky build.

If you follow that you may/may not get a fully realized character in terms of a build, but I tend to feel it's got more character, and is actually easier to RP as, than having your build planned out way beforehand. IC unless he is some kind of master game that got a hold of the alpha of SAO and knows everything in the game inside and out, most likely he's not going to know exactly how he's going to progress. Usually the term of fully developed characters in one particular area can be cynically called a "gimmick," but that's more for other games where that tends to happen more often than not, or where a build is oriented around a single ability and that's it (Ex. dropping a characters Intelligence and Charisma in order to give them a ridiculous Strength stat).

With the way skills are currently, eventually every character will amass enough points to start branching out into other areas, but the tendency is to play it safe and focus in one area first before doing so.