Time Capsule is nice but it's pricey and adds a router which you may not need.

I would LOVE LOVE LOVE to have a Drobo but you have to pay extra for the sled (for LAN connection). It's also expensive.

The next one I would look at is the HP Media Vault line. There's the cheaper MediaSmart Server which is a 2 bay version. I've lots of positive reviews on that one.

After that, Buffalo might be nice. I know some of them are hackable, making them a bit more valuable.