Ok, this isn't intended as a thread-crap, so please don't take it that way. Some thoughts:
First off, Intel and Xircom are now the same company. For all the intel cards with grey dongles with that blue plastic stripe, those are made by Xircom. Most (all?) for the past 2 years or so have been. The Intel dongles are compatible with Xircom dongles and vice versa.
Secondly, keep in mind what the dongles cost vs. what it would cost to replace the card AND dongle. Example. I got a Brand New Intel Pro/100 II CardBus for $12. That's cheaper than the dongles. Keep your eye on places like eBay and you can PROBALLY get a better than Intel sells the dongle directly for.
Also, if your notebook allows it, look closely at the Xircom/Intel RealPort line of cards. Intigrated connectors, I REALLY like them. Very good in situations where your users frequently loose dongles.
Lastly, Intel/Xircom cards are GREAT, I would say the best out there. They've got me hooked.