I have the Galaxy Tab for work. Its fine but if I were buying one for personal use, I'd get a larger one. I also have a HTC Incredible 2 for work and I don't spend any time on the phone using apps or doing anything now since I have the Tab.
I do have the data connection on it but again, for personal use, I'd probably go Wi-Fi only when getting a new one. At home, I use Wi-fi and I do the same in the office. When I travel, I could probably get by fairly easily with Wi-Fi only.