Wanting to maximize wireless efficiency...which one?

I have searched these forums for the benefits of the different AirPort wireless options, but still not sure which would be best for my situation.

I currently have my iMac and my wife's PC running off of a LinkSys WRT54G router, and things typically run fairly smoothly. However, we will be giving our kids a iMac for Christmas. Their computer will be used upstairs, approximately 45-60 feet away from the router. I eventually would like to purchase a wireless printer for them to be able to access via their computer.

So my options are:
1. Airport Express
2. Airport Extreme
3. Keep as is.

I am thinking of switching to an Airport because I assume the Apple products in the house (including iPhones) would work better together using Airport. Eventally, we will replace the laptop PC with a Mac laptop.

Keep in mind, I am not very tech savy, and if I elect to switch to one of the Airports and it is difficult to connect my wife's PC (or it simply does not work as well as my current setup), I am a dead man!

What would you guys recommend for my situation?

Thanks for all of the great advice you guys provide!

All wireless routers essentially use the same chipsets, so one brand shouldn't work better than another, although there are differences in the firmware they run and physical configuration. Personally, I use a D-Link DIR-655. My home is two stories (and a basement) and about 2200 square feet and I have no problems with reception anywhere in the house. Prior to the DIR-655, I also had a WRT54G and it worked fine as well, although range was limited out on my deck, which was to the far corner of where the router was situated.

I don't think you'll need to purchase a new router, unless of course you'd like the added range and performance differences associated with 802.11n (the latest wireless networking standard). If you do experience issues, the first thing to do would be to check the physical placement of your router. Ideally, in a two story home, it should be on the second floor and as central to the home as possible. Typically, the higher up the router is place, the farther the signal extends.

Also, there is a misconception that your Internet browser will run faster with a better router. Not the case. The fastest of internet connections only uses a fraction of the bandwidth on the slowest of routers.

The difference is in the range the routers signal can reach. Newer, more powerful routers can broadcast farther distances, but unless you are comparing a weak connection to a strong one, your Internet speed will be the same.

If an upgrade will improve your current situation, then I would do it, but there is no need to upgrade because you think you might need to in the future. Especially since a couple years from now, Wireless-N routers will probably only cost a fraction of what they do now.

Thanks guys, that was exactly the advice I needed!