Some
recommendations for routers. Linksys seems to be quite popular around here.
To work successfully wiht 10mbps you need the 11g standard, and could consider the enhanced g standards if you wished. As the speed of internet browsing ans stuff is limited byu your boradband the only beneift of the enhanced speeds would be if you move files and stuff within your network.
Often wireless networks don't quite make it at teh ful stated speed, due to local interference, range of transmission etc. The 11b standard gives you no margin if things are a tad slow.
As for cards in the PC, as indicated above, PCI will operate better as USB will take resources from your PC. However USB would allow you to move the card a little from your PC if there was a very localised wireless reception dead spot. If you PC has a reasonable spec its unlikley to be critical. If you get an enhanced speed 11g router then make sure your PC card / adaptor supports that enhanced speed.