Netbook Purchase

It has been many years since I have owned a laptop, and I haven't kept up well with any mobile computing. I am intending on purchasing a netbook; I am looking for one that can do the following, in order of importance)

1. Run QuickBooks.
1a. Feels relatively quick doing the above.
2. is comfortable enough to actually use for QuickBooks (external mouse is ok, keyboard is not).
3. Decent battery life.
4. Output HD content (not mandatory, but it would be nice).
5. 3G (I am an iPhone user on AT&T, as I understand, tethering is still not available, but if I do get a 3g modem, anyone know if I can piggyback off my existing line, or is there another mando data plan that I must buy?)

A small and inexpensive laptop might also work here, but I am intending on purchasing a decent gaming laptop in a few months (will be going on a 9 month cruise, and will need a desktop replacement; I would like to delay its purchase until I need it as I don't see myself using it extensively until that time).

Thanks for any help, it is greatly appreciated.