well robot, the old one is not as updated. The old one that I have does not support AOL, the new one does. The new one has a 128 bit encrytption, and it has two ethernet plugs, the first one only has one ethernet port. The only other thing i know is that the new one supports up to 50 Mac and PC users, while the first only does 10. anyway get the new one because of the firewall, but don't get it just because it is the new thing. The old one is just as good, and I wouldn't trade mine in for a long time.
The new one will also give you a stronger, more robust connection if you have high speed internet. I have mine at home, and I can tell you that between the two base stations, you get a better connection speed with the new one. The LAN and WAN ports are also nice, since that way you don't need a network switch it you want to attach a single network device/system to it. I have an 8 port switch on mine, with the game system, printer and base connected to it. I can put up to five more computers onto the switch (of any kind, Mac or pc) before needing to add another switch.
If you don't have a base station yet, go for the new one... it's worth the investment. Besides, you don't HAVE to go wireless with it, you could plug into the back of it and use it that way (if $$ is too tight to get the base and card at the same time).