I agree with you, however, probably 700 of those 750 channels are useless.
For a "Mac person" AppleTV is the obvious choice. In our household, while we have two iPhones and an iPad, we have 3 Windows PCs and a MacBook Pro that runs Windows as often as it runs Lion.
We have a Roku XS that gives us access to Amazon, Netflix, Hulu+, Vudu (plus a host of other services) and can access anything else through PlayOn and a PC. We also have a Panasonic BD player that also covers Netflix, Hulu+, Amazon and Vudu. My daughter has a WD Live that covers all the major services and has a Slingbox client. Of all of them, I'd pick the Roku as the best all around streaming solution available.
I'm not averse to getting a Roku, but so far haven't figured out what it brings to the table for me. 750 channels is all well and good, but after looking at all those, the majority of which are non-supported, I couldn't find any I don't already have with my setup that I would want.
I use Playon also, but only rarely as it only does 480p SD. I have to really, REALLY want to watch something to watch it in SD. Heck I'm even paying for HuluPlus so I can watch the teener targetting series on the CW!
I also wanted to mention that when I was with DirecTV about 3 months ago, my 2 HR24-500s were working very good, but they were very slow especially compared to the 2 Hoppers I have from Dish. D* really has no real excuse for the sluggishness that is pervasive across the HR line, imo.