What do you suggest?
I've downloaded a lot of games so far and the ones that I keep going back to time and time again are:
Flight Director (guide planes to a safe landing while avoiding air traffic)
Wixel (Boggle-like word game)
BitBlocks (formely Androidtris - Tetris clone)
Jewels (Bejeweled clone)
Air Attack (crappy graphics, but addictive gameplay - shoot down planes)
HomeRun Battle 3D (super nice graphics, fun game even in demo mode)
Real Blackjack (nice Blackjack game)
All of those are either free, ad-supported or demo versions of games with decent play. Have fun!
i love trap. its pretty fun
got eris: 12/24/09
returned eris: 12/28/09
got droid: 12/31/09
rooted droid: sometime in january (right after it was released (manually))
bb->2.1 sbf->desire rom> 2.1bb> 2.2
got incredible as warranty replacement 8/31/10
shattered inc screen 9/25/10-> got insurace replacement 10/4/10
broke inc screen 10/19/10-> got warranty replacement 10/22/10
got moto droid 1 off ebay 1/7/11
broke inc screen 5/26/11-> got insurance replacement inc2 5/27/11
sold inc2 & bought vzw 16gb iphone 4 6/9/11
Here are the ones I really enjoy...
Papa Stacker - This is probably my most played game so far. It's a simple concept, as all you do it try to stack blocks of different shapes in a game board and have them stay up. My girlfriend and I played this game for a few weeks back and forth until we finally completed all 40 levels last night. It starts off pretty easy, but near the end it can be extremely challenging.
Shoot U - A handdrawn game where you shoot a "ragdoll" out of a cannon, trying to reach the goal. There are all kinds of neat obstacles in the game to try to make it through.
Space Physics - This is a really neat concept. You have to move a ball to the final goal by drawing lines, wheels, etc. to get it to that point. Anything you can draw can be used to move the ball toward the eventual goal.
All three of these games were made by Camel Games, I believe. I think they also did Flight Simulator, which I have heard is a good game. It's not really my cup of tea though. For my money though, Camel Games is making the best stuff out there on the Droid right now.
Some other games that I enjoy...
Homerun 3D Baseball - It's been mentioned above, but it's a simple and fun game where you can compete against others in homerun competitions. It's quite addictive.
Spades - A simple version of Spades.
Monkeykick - There isn't much to this game, but it keeps me entertained when I have a few minutes to kill. Basically, you are a monkey and you are trying to kick a soccer ball as far as possible. That's it.
I have a lot of other games downloaded, but I've been really focused on Papa Stacker and Space Physics since I've had my Droid. Now that I've finished both of them, I'll probably start moving on to the others that I've only played briefly, like Bebbled, Buka, and a few others.