I would like to make one of the computers wireless and add another computer while still maintaining a DSL connection and firewall.
I have looked at the new Linksys wireless routers and I'm not sure what the best decision is. Reading the specs, it looks like the new "g" version has the fastest bandwidth. This would be very useful since we often ship large video files across our network.
My question is, what's the best product to meet my requirements? An 802.11g AP, a dual-mode 802.11a+g AP, or a wireless AP + cable/DSL router?
What kind of AP do you need? Because you send video between stations on your wired LAN, you want your wireless LAN replacement to be just as fast. A standard 802.11b wireless LAN is slower than your existing Ethernet, but faster than your DSL uplink. If you choose 802.11b, you probably will not see a difference on Internet downloads, but you will see a difference between stations on your wireless LAN.
If you have a full-duplex FastEthernet (100 Mbps) LAN right now, then 802.11 wireless simply will not be as fast between your LAN stations. If you have a full-duplex "regular" Ethernet (10 Mbps) LAN now, then either an 802.11a or 802.11g LAN will be comparable (~20 Mbps, best case, when stations are close together).
Choose 802.11a if you don't need to be compatible with either 802.11b or 802.11g and you will buy 802.11a adapters for all stations now. Choose 802.11g if you need to be compatible with existing 802.11b adapters or would like to be compatible in the future -- for example, many new laptops ship with integrated 802.11b cards. 802.11b is slower than 802.11g, but (unlike 802.11a) 802.11g gives you the possibility of compatibility with slower devices. There's no reason to spend extra bucks for a dual-mode A+G router unless you actually need to deal with a mix of A, B, and G stations.
Given this and your preference for Linksys, you're probably comparing a Linksys WAP54G (802.11g AP) and WRT54G (802.11g router). Since these two products are comparably priced, you may as well purchase the wireless router.