If the dual-band WiFi-n support of the new Apple Time Capsule strikes you as something work having, but you're all set for backup, then you'll want to be looking at Apple's new AirPort Extreme Base Station. It supports up to 50 users across both the 2.4GHz and 5GHz bands simultaneously, offering maximum range, compatibility and throughput.
There's also guest networking - a separate SSID with a unique password, to let visitors online but not access to your shared computers - and printer sharing via the AirPort Extreme's USB port. Alternatively, plug in a USB hard-drive and you've cobbled together your own Time Capsule equivalent; if you're a MobileMe subscriber then you can access files on that drive over the internet.
The new Apple AirPort Extreme Base Station is available now, priced at $179. It's listed as shipping within 24hrs.