In the past I used to pack my textures into POTs, however I'm told that this is fairly redundant with NPOTs supported by most cards.
So, what exactly are the limitations of NPOTs? - I know they don't support repeat wrapping, but I'm used to this with my own packed textures anyway. Are there any other limitations?
How about support? - how old does a graphics card need to be to not support NPOTs?