For a long time I was a Rebellion guy, but ventured over to the Marquis pizza after a few recommendations from friends. They serve up an amazing thin crust pizza with daiya and a huge selection of vegetables. The prices are pretty average, and I don't know if you can get vegan pizza by the slice, but that would be awesome.
A month ago they had a "meatless Monday" where 10 bucks got you unlimited vegan pizza all night. Needless to say, it was amazing, and here's to hoping they have another Meatless Monday in the near future.
All in all, I think the Marquis has taken the top spot from The Rebellion as my favorite vegan pizza stop. Make sure to specify vegan, as they serve omni pizzas as well.
Cons: price, lack of seating