get armstrong tickets for sure. ashe is crap the first whole week. armstrong is magical, and there's a part of the stadium where you can walk from inside right to the grandstand court. it's pretty amazing.
bottom line: you can get a good seat in armstrong for cheaper than an ashe ticket, im pretty sure.
anyway, a little tip for ya if you REALLY need to get into ashe, you can wait at the exit and ask people who are leaving if you can have their ticket for the rest of the day. i know people who have done this for years, and though i've personally never done it, it seems like it would work because so many people leave early.