Hi,
I really like the Linksys wrt54g. I've got 3com, dlink and even gigafast (cheap but reliable) units. I still use my fileserver with the wired and wireless units.
The outside use will depend on the type of construction for your walls. Metal is a no-no, brick/block/concrete reinforced walls can be a major concern. Wood construction can be a problem if you have multiple walls to pass. You can purchase or construct a directional antenna to control your signal transmission concentration.
You say you will locate in your basement office. Might I suggest you place your router/wap of choice in the upper portion of your home and wire to your office. You could use a switch at your office location to allow multiple wired units within the office.
I located one of the wireless units in our family room on the first level (ranch) then wired to the lab/office area located below and about 50 feet from POS. The recreation room (lower level/basement) is wired and wireless (B/G).
I use the fileserver for peripheral service and file exchange. I have ADSL because we are just 10,300 feet from the POS and we cannot get cable tho it is just .2 mi from us. The network is setup with a DMZ with the 192,.168.0.x. I would suggest once you setup your network to check it using Gibson's site
www.grc.com.
My home is brick and the closest neighbor is 300 yards away but he is surrounded by wooded area. I do get access from my patio but it is only 20 ft from a WAP.
You should also be aware of possible interference with other wireless devices within your home. They sometimes can cause problems with your wireless network. You can usually change the channel for your network unit to overcome the overlap.
Another suggestion is don't go cheap on your choice of cable for the wired network.
I have several out buildings that I want access to the net and I will probably use a microwave link since they are at least 300 ft from the house. A simple antenna system using old sat antenna will work for this need. I will not be able to use the original lnb but will build a simple antenna. This will be a line of site unit.
I mention this because you should select a good location for your unit to allow wireless access for your convience. Since
you mentioned the use outside. Be aware that you should use wep/wap to at least limit or control access to your network.
This will keep the honest people honest! If someone wants to get access to your network, even with wep/wap, it can be broken into with some effort.
Secure! Secure! And then more security!
Sorry about getting so winded!