Does anybody know of some good arcade puzzle/block Tetris type games? Games like Klax and Sen-Know?
Preferrably with lots of sprites and flying colors and whatnot.

Super Puzzle Fighter
Money Puzzle Exchanger
Tetris Attack (don't know if there's an arcade version of it)
Puzzle Bomberman

Columns, Columns 2, and Columns 3 (Genesis). Some of the best puzzles ever.

Check out Mean Bean Machine on Genesis and Wildsnake on SNES too, if you like consoles.

You can try that pokemon puzzle league on n64. Just ignore the pokemon... which is hard i know... but it's a good puzzle game. Or you could just get Tetris attack which is on SNES which is just as good.

For arcade you can try those puzzle bobble games or magical drop games. I hear theyre pretty good as well.

Not just pretty good, excellent. Uo Poko needs more recognition.

Did anyone play Zoop?

Magical Drop 3 is probably the most fun multiplayer puzzle game I've ever played. Yes, it can get *very* competitive. Back in '99 or 2000, a friend and I even wrote an FAQ with all the attack patterns and general versus strats. Shame we didn't upload it anywhere, since others have done the same since - but ours was better and more complete, with full ratings and explanations and such. Oh, and MD3 fits the "flying colors" description to a T.

All the Puyo-Puyo variants are also awesome. There's a very atmospheric fantasy-style game called Karian Cross which is supported by MAME, which is pretty much a puyo-clone but not exactly. Worth a try.

People also seem to love Super Puzzle Fighter, although I never got into it that much.

Btw - does anyone know if Pnickies ever got an arcade release? It looks like it's unfinished.

[edit:] I just remembered Land Maker. Weird, different, but very cool.

Yes, it's on CPS-1 hardware. Made by Compile/Capcom.

EDIT: The same Pnickies is also on the CPS-2, but it's a prototype.