It depends on what you are looking for. If you want to maximize your functionality pick either a 9.7" 4:3 or a 10" 16:9. If you're wanting a balance between functionality and portability then get something around the 7" size. I personally wouldn't go any smaller than that, but I have my android smart phone for that. Now you can get cases with usb keyboards that are made for a smaller screened tablet. SPEMALL sells them for their chinese tablets. The form factor for the case itself is the same, but the pieces that hold the tablet in place have been adjusted. This helps to increase the functionality of a tab that's around 7". I have an ASUS Transformer tf101 (10" 16:9). I also have a Ainol Aurora on the way (7" 16:9). After using the ASUS for a while I can see the benefit of a slightly smaller tab in terms of general use of surfing, reading, and playing games. However, the ASUS for all intents and purposes is a laptop replacement for me. It does everything I do on my computer with greater mobility, quicker start-up/shutdown, and program loading. All I can say is I'm very glad that I decided to get one!