I currently have a Linksys WRT54G.  Only problem is it's in the basement (no way to get it to the top floor, where my new gaming rig will be due to wiring restrictions).
 
Up 'til now I've had just an IBM Thinkcentre on the top floor with a big antenna attached to the D-Link wireless card.
 
Now that I want to game (mainly World of Warcraft) on the new rig, and can't move the router to actually get wired ethernet from it on the top floor, I want to buy or do something to improve the wireless connection to gaming levels.
 
Any suggestions?  
I know wireless N routers may help, but the spec isn't official yet so I don't want to buy something which may become obselete.
Or do I just need a repeater.
 
 
Alternatively, a question:
I always get about 54mbps on the top floor PC right now.  Is that fast enough to play online games on like WoW?
 
If so, maybe I don't have to do anything?

Have you considered Powerline Ethernet Adaptors (connects network through standard power cables in the home)?
 
http://www.dabs.com/ProductList.as [...] archType=1
 

That's an amazing solution.  

Is the Linksys PLE200 a good one?  I think I'm going to give it a try.

Looks like the Netgear 2-pack HD Powerline adapters are the best.
 
I'm going to see how my existing wireless connection does first.
 
I'm getting 54mbps right now on it, and this adapter says you get an avg of 52.7, but up to about 200mbps, so not sure if it's going to be a noiticeable improvement or not.

not sure which to go for.  I've only installed them once for a client and can't remember which they were.  I had doubts, but they do exactly what they say.  Plug in at router & one at PC, connect cables and it just works.