On my laptop i'm using a Netgear WG111 802.11g Wireless USB2.0 Adapter and Netstumbler. My laptop also has a built in Wireless adapter.
When i use Netstumbler to search for APs with the Netgear Adapter, it will pick up an AP after about 10 minutes (even if it's right next to it), somtimes it won't pick it up at all, and other times it takes about 3-4 mins etc etc.
When i use the builtin Adapter and netsumbler it picks up the network instantly.
Using the windows wireless internet program the Netgear adapter picks up APs instantly, and so does the builtin adapter.
I haven't been able to test another USB adapter of the same model, or a different one yet.
If you want to know the reason why i want to use the external adapter its because i'm putting it onto a dish or up high for better transmission and reception.
Also, off topic, i when signing up to these forums i tried to use my hotmail email and it said that the administrator had banned my email address???