I've been toying with one of these that I picked up at radio shack: http://www.seeedstudio.com/depot/28-tft-touch-shield-p-864.html?cPath=132_134
The biggest problem I'm having with this screen is that it does not appear to have a proper standby mode. It has a standby mode, but all using it does is turn the screen white leaving the backlight on which kind of defeats the purpose.
So I'm looking to see if there are any acceptable low cost alternatives that anyone here may have experience with and knows works. I need it to be at least 2.8" or 3.2". Minimum 240x320 pixels. 4.3" with increased resolution would be nice as well if there are any that are cheap enough. I see quite a few low cost touch LCDs on ebay, and found a couple set up as shields like the one I have now, and have a similar looking command list to this one. But I don't know if they may suffer from the same problems since they are very similar.
The other problem is even with the 240 x 320 pixel one, drawing is slow. Erasing the entire screen takes a noticeable amount of time and you can watch it erase as if it's a fade out effect between two slides. But I'm guessing this is primarily a result of the arduino as the control. Since the code that erases the screen is actually just going in and filling each pixel in with a single color. So if there is one that has it's own controller and such that I can simply communicate with and tell it what to do from the arduino that would be ideal. I know there is the 3.2" and 4.3" 4DSystems screens on Sparkfun that can be completely programmed on their own and stand alone from an arduino board. But they are a bit more than I was wanting to spend on this atm, with the 3.2" version costing 85 dollars and the 4.3" version costing 135. Was hoping to stay under 40 or 50 on it.
Jameco has a capacitive touch 4.3" LCD unit at a pretty low price of $70 dollars for capacitive (http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2157554_-1), however it doesn't have a controller and I highly doubt the arduino would be able to control it very well. And I really have no clue where to even get started with something that could control it. I asked about it in another thread but didn't really get more than a parts list and haven't been able to find any getting started guides yet.