Re: DVD+R and DVD-R
I think that the + format is more compatable with DVD Players that are more than a year or two old. Most DVD players made these days will play both fine.
If you are using them just for data storage though then there really isn't much difference. Just don't go for anything too cheap. Look for a named brand like RITEK that is on special offer (as mentioned above) and go for that one.
Desktop - AMD 2600+ Athlon , 1GB DDR, 256MB 9550 ATI Radeon, 120GB Hardrive.
Laptop - Compaq Presario 2500.