I bought a Linksys WRT54GL today, to replace our aging DLink DI-624 (it had been acting pretty flaky as of late). The Linksys router supports open-source firmware, and our first course of action was to flash the highly recommended DD-WRT distribution. I have to say that I am very impressed with this firmware. There are lots of options available and it reports lots of interesting information.
Setting up the router wasn't difficult, but my dad and I ran into problems getting our IBM laptops connected wirelessly. All of our other machines were able to connect without any problems, so it was clearly a problem with either the ThinkVantage Access Connections application or the IBM wireless adapter. We spent quite a while trying to get things working, and finally found the issue. We had originally set the Wireless Network Mode option in the router basic setup to "G-Only" mode since we intended to use 802.11g only around our house. But for whatever reason, the IBM laptops didn't like that. Switching the option back to "Mixed Mode" cleared up the problem immediately, much to our delight. Hopefully this little tidbit will help out someone else facing the same problem.