ralink is a good choice, and they are simple to get operational..
I use a rt2500 card (Asus WL-107G PCMCIA ) in my laptop with Debian and it works great. the card was very inexpensive as well at newegg.
here is a reference for other option.
Just beware that some manufacturers change the chips used in their cards as frequently as I change underwear. Nothing like ordering a card that is supposed to have a broadcom chip and receiving a card that has some bizarre unsupported CHIP in it, while the card maintains the same model number just a different revision code.. Took me 3 orders of different cards to finally get one that was right.