I've used both Belkin and Linksys wireless routers and I found the Linksys one to be much better in terms of configuration options and signal quality.
I've also used Belkin USB adapters, and I found them to be OK, but not great. Granted they were 802.11b adapters, but the range wasn't the best and the configuration software was problematic at times.
I have the Linksys WRT54GS, and if memory serves me right, it cost about €60, but it was worth it.
More information on wireless routers can be found here:
Wireless Router Reviews