NetLion, sounds like a fairly typical experince, and a point I forgot..
Combo drives are inherently more stressed, due to the extra weight and complexity of the head assembly.
You also put more wear (or perhaps most importantly, more dust) into the one drive if you have to open/use it for everything.
The only time I might consider a Combo, is inaddition to an existing CD-ROM drive, and I'd continue using the CD-ROM drive for anything that wasn't writing or DVD.
Next question, perhaps, is choice of drives...
My DVD-ROM, A Delta OIP DV1200, is apparently RPC-1 as standard - apart from that, and usable C2 support in EAC (not checked quality though), it's not a specially good drive.
A friend has an LG DVD-ROM with rather poor CD pickup.
I guess, though, a pair of LiteOns would be an obvious choice - though a different combination would be stronger on protected audio CD (Plextor?)