First, I would go with a wireless N router even if all of your devices are G because being the center of your network is your router's job, and you need to upgrade form the center of the network out to get any upgrade benefits.
Second, to get the highest speeds when you finally upgrade your computers to wireless N, get a dual band router. Dual band is 2.4GHz and 5GHz in the same router. The 2.4GHz band is pretty crowded with cordless phones, microwaves, Bluetooth, and neighboring Wifi networks. Also getting a dual band router lets you have G and N devices on the same router, but on separate bands so the G devices don't slow down the transmission between the N devices and the router.
I like routers that have the ability to reflash the router firmware with 3rd party firmware like DD-WRT
. I like the 3rd party firmware because it has almost every setting that you can get for a router and some extra software to handle other tasks too, like DNS naming and bandwidth monitoring.
Linksys seems to have seems to have routers with the features listed above. I have a Buffalo G router that works great, but Buffalo doesn't have a US version of a dual band N router yet.
EDIT: Netgear has a router that meets the three items above called the WNDR3300