PCI or PCI-e? I've got an abit Airpace card, which fits into a 1x PCI-e slot, and it's bloody brilliant, has a decent aerial even out of the box, and really easy to modify and add extra cooling to for a high-gain jobby. Very cheap too, and the software's great.
The D-Link DGE-560T adapter is quite good, you can have a look at it: http://www.dealstudio.com/searchdeals.php?deal_id=71715
I have always found Netgear to be the best wireless (for home) for routers and cards (as long as you use their software). Intel have always made good laptop wireless cards and great other network cards, so they may be worth a try.
$100 will get you any make/model you want... including wireless 'N' products (the fastest currently available - here in the UK at least)... such as the (ridiculously long URL'd!) Linksys WMP300N Wireless-N PCI Adapter...
