In all groups I've played except one we simply didn't use anything else than papers and books during the game, while of course everyone was free to use a PC or whatever between games for keeping track of characters, writing sheets and note etc.
In one group where I instead am the DM I've been using a laptop both for the 3.5 SRD and as a DM screen

I really prefer that in the games I run personally the table is as empty as possible, which means that if players only have dice and character sheets, while I handle maps and pictures and keep the laptop as screen, that would be the best.
Books usually sit on a chair beside me. Players don't really need the books themselves during game if they trust me enough (they don't always...). Of course I have never forbidden their books, but when we need to check a rule, this is what often happens:
- I check the SRD and tell the answer in a few second (or adjudicate in a not so longer time, if not covered by SRD)
- players take out their PHB and start browsing, time flies...
- each player announces he has got how the rule works, but each player has a different conclusion
- I have to point out to each of them how they were reading only the sentence they wanted to read, and not the rest of the paragraph
- after 5 minutes instead of 20 seconds, game resumes
Anyway, I don't really need that laptop myself, and I have run so many sessions without it in the past. But I have to say that since Sovelior wrote the SRD in HTML, checking a rule takes a very short time. When I don't use it, it's because we're also playing other adventures in 3.0
Oh and by the way, playing another game or surfing the web on a laptop during D&D is just as an idiot behaviour as reading the PHB (or any other book) while you're playing Warcraft on line. And since you're gaming with others, allmost as unpolite as brushing your teeth while you're still eating your dinner in a restaurant
