Agreed on most of the points above, however most devices can cope with 64Mb (or more) of uncompressed textures. Doing some tests on your target devices like Developoid said is very good practice. On the devices mentioned above (4S, S3) we got a game with over 100Mb of textures to work with no problems. Bandwidth-wise, this is less of a problem as you will be compressing your textures, presumably using 8-bit PNG. 64Mb of uncompressed textures can easily be compressed into 4 or 5 megs (depending on your art style). Again it does depend on your art style, but most people won't expect more tha