In near-field placement, the VTF2 would be sufficient for most people, but the VTF3 would absolutely rock. It has roughly three times the output of the VTF2 and is not even twice the price, so it is a real bargain. Anyway, set up an appointment to go demo Hsu's stuff. As for bookshelf speaker fronts, you don't quite understand. Tower speakers are no more capable than a decent set of bookshelf speakers when you use a properly integrated sub. Yeah, you can migrate the bookshelf speakers to surround duty if you replace them with towers, but they better be some seriously good tower speakers to net you an audible gain.
As for receivers, whatever receiver you should get depends on the features you want. Regarding used receivers, you might want to go with craigslist on that one. One time I bought a used Pioneer Elite off of ebay, and this 70 lbs behemoth was sent in a box with only a smattering of foam packing peanuts for protection! Nedless to say, the chassis arrived bent on that receiver. You have to be cautious when buying from ebay.