I've tried several mini-pci cards over the last couple years, startnig with an Intel 2100b. Then I went to a Dell Truemobile 1300 (b/g), when the F.51 bios came out and would not work with non-HP/Intel cards I switched to a Intel 2200 (b/g) but the range wasn't great. I've since moved back to the F.34 bios (works fine) and I bought an Atheros 5004X based card pulled from a Toshiba, it's A/B/G also and will work with any network. The atheros also has longer range and higher speeds.
If you buy an Atheros make sure you get a 5004 or later. There are 5001 and 5002, but they are the older slower models, and there are X (a/b/g) and G (b/g, no a) versions. Ebay has them a lot pulled from other computers for about $35-50.