I think there's a general feeling that PCI is preferable to USB -- remember USB was originally developed for simple stuff like mice.
If going for wireless N stick to the same brand of router and adapter.
That's too bad because I have Linksys products (like them and happy with them) now but found a D-Link PCI-e Wireless-N card on Newegg that fits the bill. http://www.newegg.com/Product/Product.aspx?Item=N82E16833127218
Is switching brands better/worse than trying out USB?