Processor speed really doesn't matter as much as from factor, connectivity and screen quality, which are the true differentiators between Android tablets. There are trade-offs between how light and thin a tablet can be and what kinds of standard ports (HDMI, SD, USB, etc.) it can support, so the first thing to consider is whether it's more important to you to have something thin and light or something heavier with better I/O capabilities, and perhaps more rugged too.
Most high-end Android tablets today have 1280x800 screens, but both ASUS and Lenovo have announced 1920x1200 10" tablets for the 2nd quarter of 2012. I'd guess that by the end of the year, that will be standard for high-end Android tablets, particularly if the next iPad has 2048x1536 resolution, as rumored.