My BF has an iphone and not many docs are made for it. He either has to put the phone in airplane mode (and therefore not receive any calls/text) or there is horrendous feedback. I think the iPhone is also overkill unless you are in the market for a new phone also.

Aside from that: pretty much 90% of accessories out there are for ipods. Most other devices just go by Aux in instead of a native dock. You can't charge AFAIK from an Aux in unless there are MP3 players out there that allow that. If you plan on listening all day like at work I'd rather know that my ipod will be charged and I don't have to constantly charge it when I get home or have it plugged in somewhere else too. With my Ipod docking station I have a remote that can control my 30gig ipod. I don't think aux in allows that either.

Unless there are docking stations built for the specific brand you buy you will get more features out of an ipod dock.