Yeah, the scanner makes a huge difference, but it cost a mozza! $700 was the cheapest price I found, but I wanted one that did slides and negs well and this was the one that always got the best reviews for a flatbed scanner.
I priced getting the slides and negs professionally scanned, and that was aound $1 per slide - and they wouldn't take the care that I would anyway..
Bought an Epson V700 Photo. Will scan 12 mounted slides at once (to seperate files), or 24 negs. It has it's own seperate Hi-Res lens specifically for negs.
I then bought better software to run it - Vuescan. I allows you to set your scanner model so the software can compensate for any scanner shortcomings, and it even allows you to tell it what type of film stock it's scanning so it can compensate for the differences between ektachrome and kodachrome etc. (from memory kodachrome had better colour but only available in 100ASA, ektachrome was available in 100, 200 and 400ASA but the colour wasn't as good)
The software will even make multiple passes with the scanner - scanning for highlights and lowlights and then merge the two scans for a better dynamic range...