Wireless network adapter

One of those long aerials that plugs into the Ethernet socket... I think they call them Cat5e patch leads :-)

Otherwise, pick one from amazon (or similar) which has good customer reviews and an external aerial.

If you want to transfer large files between computers, you'll be disappointed with the speed of wireless data transfer compared to Gigabit Ethernet.

The adapter would depend on the type of connection you are using to connect to the access point. If using multiple what do you use the most? (N/G/B/A Wireless?)

The best WiFi adapter for the client depends on the router (WiFi AP).

Yes. This is a place not to mix 'n match brands. Use the same brand as the router.

Personally, I use a linksys wrt54g router flashed with ddwrt as a wireless NIC. I use it as a client bridge, so that one office (with multiple wired devices) can talk to my other router. It's excellent because it lets you adjust the transmit power a lot higher than you normally can. Using a different linksys WNIC, I saw around 5 SSIDs when I scan for networks near home. With the DDWRT router/NIC, I see 50!

festerovic, is there a guide for flashing a linksys router with ddwrt? I would like to try this new technique out.

masterofcheese,
Well, the instructions are slightly different for every router. First, if you have a router you want to try, check the supported models page, found here:

http://www.dd-wrt.com/dd-wrtv3/dd-wrt/hardware.html

Then, click on the link for the model. On the page, it might have separate instructions. But basically, if you were to do the steps of most routers, it involves flashing the firmware to a generic version of ddwrt, then flashing with the model specific version.