Dan,
It depends on whether you just want it for internet sharing or if you're planning on some hard-core local area networking.
What I think most people don't realize is that average internet speeds are well below the 54mbps that wireless "G" offers. Most cable users around where I live max out at 5-10Mbps, which means that even 802.11*B* would be enough!
Now, if you have a business cable line (which can push 17-20Mbps) or FiOS (which usually hits 20+, but can hit a "theoretical" whopping 50Mbps), you'd be bottlenecked by the slow "B" wireless speeds, however still well within the 54Mbps of "G".
So, no, "N" would be an utter waste of money in my opinion. If you're doing a lot of local networking, however (such as NAS, Apple's Time Machine, or transferring large files between computers at home) then you'd benefit from all the speed you can get. However, keep in mind that most routers will only go as fast as the SLOWEST connection, which means that even if your router and laptop are n, if you connect your Wii (which is only 802.11g), the entire network will be reduced to G. Even better, if someone comes over with their PSP, the whole network might slow to 802.11b!!
Hope that helps...