£1,500 is a lot. I'm not sure I could persuade "er-indoors" that it was a vital purchase!
I've got around 2,000 slides, both 35-mm Kodachrome and 2½-inch square Ektachrome. The 35-mm slides are normally viewed with a slide projector whilst the 2½-inch slides have been scanned in and are now backed up digitally. My current scanner is a 2-3 year-old Epson Perfection 4990 Photo that works very well and has suitable masks for scanning both slide sizes.
As a bonus Epson have posted Vista drivers on their support web pages so the 4990 works well with the new OS.
Tony