I would say either a Linksys WRT54GL (as you mentioned) or the Netgear WGT624v3. I own the Netgear WGT624v3, and it is a pretty much rock solid router. It holds a very stable connection and the port forwarding works very well (I run a lot of server applications). However, the WRT54GL (Not WRT54G) is an open platform router with many 3rd party firmwares. That means you can add many features that would never be found on any home router, and essentially turn your $60 router into a high quality $100-$200 feature network device. I don't have a WRT54GL, but if my Netgear ever dies, I'm buying one.
While Wireless N and Gigabit LAN sound nice, you need both ends. Your PC needs a Wireless N card (most laptops have integrated Wireless G, which won't work any faster than 54mbps with any router) and almost all PC's have normal 10/100 Ethernet cards (only work up to 100mbps, no matter how nice your router is). If you have a gigabit LAN card or a wireless N card in your PC, you'll probably know about it. In that case, go with the nicer router, otherwise stick with the 10/100/Wireless-G routers.