alien swarm

I've been playing the CoH: Online Beta for a week so far.  It feels pretty good.  I can see where they can use the micropayments but obviously right now they do not have it set up.  It does look like you can do plenty without paying anything in the game.  The people that pay may have a slight advantage but it is a bit early to tell. 
 
I also play a lot of League of Legends and that game is just fine without the micropayments.  They do something a bit cheap which is allow people to spend money to level up faster, but other than that you can pretty much skate by with just playing the game and using their regular points to buy everrything.

The good "free to play" games are usually open source titles, not F2P games based on big franchises.

Warzone 2100 is a great free RTS (which was originally a retail title), Quake Live and Battlefield Heroes are not bad either. FreeCiv is an awesome Civilization clone.

I tried Lord of Ultima and Legends of Zork for a while, but got bored as they really didn't offer any gameplay, it was just "You can press a button 30 times today. If you want to press the button more, you can buy more button presses for real money in our store!". When you pressed the button random things happened, you killed something, got some loot, leveled up, but you had no control at all over what happened, only the pace - based on how fast you spent your daily button presses.

> > Are you playing any of this stuff?
 
HELL NO. Why the hell would I play a "free to play--but pay us after you reach level 10" trial? If I wanted to do that, I'd download goddamn DEMOs of games and then BUY the full version and not be nickle dimed.
 
I will however say that the only "free to play" game I am half interested in is Q3A's Q0/Quake Live, and that's only because I put hours into Q3A back in the day.

I played Gunbound and it was alright (good thing there were servers where equipment didn't matter). I played GunZ and didn't really enjoy it.

It really depends on what kind of experience you are expecting going in. Since I don't have a console right now, I've been playing several of these, and some are not so bad. I love Gunbound as a game but it becomes unplayable after the beginner levels unless you pay up. 
 
Tiger Woods Online: I played through beta so I was already hooked in. I haven't put up the 40 bucks for a membership yet. As a golf game it's still playable as you can still get better through gameplay. It is annoying to only have one or two courses free to play at any time. 
 
Battlefield Heroes: I had never played the series before so I didn't really know what to expect. I'm enjoying it right now because its fun and there aren't many game-crippling advantages that come with paying. Better weapons, yea, but I can still get kills and contribute. 
 
I was excited about NFS World because I liked Most Wanted. I was OK with going back a few years. I'll probably play through to the cap, but then I'll put it aside. Haven't dropped any money yet and nothing to really make me want to.

free to play could be ad long as the game is actually good

Free, in most cases = spectacularly bad (See: XBLA Yaris) Not that I havn't tried my share of free games, and some of them are great!