I finally got a Galaxy Tab 7" and start playing with it. It's a nice tab, small enough to be handled using one hand, and big enough to easily browse web pages or access servers over RDP. But...
Yes, there's a "but". After two days of use, I changed my mind about 7" or 10 ". The size matter, and the size is related to the use you'll do of your device.
For business and traveling, I think the 7" is more suitable. Small enough to be carried around easily, and the weight doesn't matter too much considering the dimensions - some extra weight will not make you suffer while carrying it.
Aside, if your main use is at home, I think I'd more like a 10". The bigger display let you read more easily even comics, and size doesn't matter so much as long as you just out it around on a table. What it matters, however, is weight. It have to be light, and thin too. Because you'll have to handle it most of the time, all around your house, and if you read comics or books too (as you'll probably do)... ever read e HUGE HEAVY book? :)