I recently purchased a 15" MBP and I have it hooked up to a 20" Dell Ultrasharp Widescreen monitor. The Dell monitor has a DVI port, but I don't have a DVI cable, just the VGA cable. I'm currently using the DVI-VGA converter that came with my MBP, which works fine, but I'm wondering whether it's worth buying a DVI cable. Does the DVI cable make any difference? Thanks.