Well, the first thing you may want to consider is NOT going with a Verizon based phone.  Verizon has been known to cut users off for using too much bandwidth.  Now, no one with a 3G phone that I know of has been cut.  It's all been people using EVDO cards.  But that doesn't mean they won't.

Sprint, OTOH, has what many people think is a better network and they don't limit your data use like Verizon.  Search the forums here and over at PDAPhoneHome for MUCH more discussion on this subject.

I have a Treo700W so I'm a Verizon user, but I didn't have a choice as my boss gave me his phone.

Now as to the phones, the 700W is a decent phone.  The Q is thinner but wider.  Also, the Q is a SmartPhone and the 700W is a PocketPC Phone.  The main difference is that SmartPhones don't have touch screens and they also kinda run Win-Mobile inside the phone's own OS.  Because of the lack of touch screen the SlingPlayer software is very different.

I prefer the PocketPC devices to the SmartPhones. 

Slinging with a SlingCatcher, a ProHD, a Pro, a Solo, an AV, and a Slingbox Classic. 3 Replay TV units, a Roku Photobridge and a Roku M2000 Soundbridge, an AppleTV, a Vudu, and digital cable. www.na9d.net

The Treo 700p through Sprint runs Palm (not Windoze) and has a touch screen interface.  It is also very reliable.

The Slingplayer software should be out any day now (I hope) for the 700p too.

"The significant problems we face cannot be solved with the same level of thinking that created them." -- Albert Einstein