I think re-issues are good some of the time. As others have mentioned in the thread, Metal-Mind have some excellent re-issues. They have bonus tracks and are limited to 2000 (something not everyone cares about, but I as a collector enjoy owning that sort of thing).
I like to be able to put my music onto my computer, either it be ripping vinyl or CD. Sometimes I use the vinyl rip, sometimes the CD. Just depends which one I think sounds best. I don't think you can say all re-issues are bad, but I am not saying ther aren't bad ones out there. Theres a version of Megadeth's KIMB that has bleeps everywhere there is a swear. Totally ruins it.
I own a few albums on both Vinyl and CD. Blind Illusion's Sane Asylum, Carnivore's debut, just about every Judas Priest album. With some vinyl, especially my Priest, they are pretty old things and don't play well anymore, so ripping the vinyl is out of the question, so thats why I think the CDs are great.
Really though, it all comes down to taste and what sounds better to you. Then again, it also means spending money if you are actually going to buy the stuff. I'm all for re-issues. I am strongly against re-recordings though.