I'm sure this discussion has been done a bazillion times before, but how about lately?
I find that I really like playing a Sentinel-Weapon Master.
One of the nice things about KotOR2 over the original is that skills really mean something this time, so I like to go crazy with skills in the first few levels. I start out with 14 intelligence, and spend a feat on making Repair a cross-class skill fairly early on. I then pump the crap out of Treat Injury, Computer (to upgrade T3-M4), Repair (to upgrade T3-M4), Persuade (for dialog options), and Awareness (dialog options and avoiding mines) for fifteen levels until I can switch to Weapon Master and beat the crap out of everything (with lots of +strength items, Master Speed, and a decent lightsaber, you can one-hit most things).
Forgive the vagueness of this build, but I'm lazy.
Progression: two points into constitution (for the nifty implants), then all remaining points into strength
Computer Use: 4
Treat Injury: 4
(Note: class skills in yellow, non-class skills in red)
Spend points on Computer Use, Awareness, Persuade, and Treat Injury until you can spend a feat point to make Repair a cross-class skill. Then keep Treat Injury maxed, and keep the other four skills roughly equal (they should only be a couple of points behind Treat Injury). By the time you choose a prestige class, you should already have enough in Repair and Computer to get all relevant upgrades for T3. What you do with your skills after you get all of T3's upgrades is up to you, because it doesn't really matter so much after that. By then your secondary skills should be more than high enough to cause lots of trouble hacking computers, repairing robots, and talking people into giving you their last pair of socks.
One point in Demolitions is a personal thing. I find that certain things in Peragus are easier if you have a point in Demolotions. Namely, when you pull components from the hordes of reprogrammed robots, you can blow them up so that you don't have to keep track of which robots you pulled components from already or not. Also, if you throw one more point into Demolotions, you can recover rather than disable mines. I use a lot of mines in the game for Atton and Mira's solo bits, so it never hurts to stock up early.
One point in Security is more than enough for most locks in the game. You can keep an NPC with a high security skill in your party for those few locks that you can't open yourself.
Keep at least one NPC around you who has Stealth and Demolitions pumped up very high so they can recover mines while stealthed (happens numerous times in the game). Whatever character(s) you use for this function is probably a good candidate for leading the assault on Freedon Nad's tomb on Dxun (the party that goes without you while you and another party heads for Onderon). Bao-Dur, Atton, and Mira all perform well in this capacity. Mira works best to lead the tomb raid because while she is selected, your other party members can't accidentally trip any mines.
First feat: Repair (cross-class)
After that, whatever works for you, but spend feats with the expectation that you'll be a Weaons Master (guardian prestige class) later. I max out Dual Wield and Flurry.
After I choose my prestige class, I pick all the nifty Weapon-Master-specific feats that further enhance lightsaber use and dual-wielding. (Max out Weapon Specialization: Lightsaber, Superior Two Weapon Fighting III, Superior Weapon Focus: Lightsaber.)
Excess feat points can be spent on Toughness and/or Conditioning and/or Jedi Defense or whatever floats your boat.
Of course you want to max out the force powers included in Force Enlightenment (speed, armor, and valor lines). Also, some kind of crowd control (e.g. Force Wave) is a really good idea. After that, do whatever floats your boat.
Sorry, but here's where I get even more vague on you. Wear the nifty Wisdom-boosting headgear (can't recall the name... the +5 Wisdom one, which makes up for your dismal Wisdom score) and every strength-boosting item you can get your grubby little hands on.
Since your Dexterity is relatively low, you can wear the Zeison Sha (or similar) armor without worrying about the max dexterity bonus associate with it. Make sure you keep a high-ranking Biorestorative Underlay and a high-ranking Energy Shielding overlay in it.
For your lightsaber, you'll have tons of feats to improve your to-hit bonuses once you become a Weapon Master, so just pack your double-bladed lightsaber full of every damage-enhancing widget you can cram in there.
Anyway, what's your favorite build?