I own a Perfection 2450; it's pretty nice for the price. I needed a scanner that could do both flatbed work as well as film/negatives. I like the 2450 because it can scan my medium- and large-format negatives as well as 35mm. It does not scan as well as a dedicated film scanner does, but it's perfectly adequate (IMHO) for scanning for the web or casual prints. If you want to make prints for sale or to hang in a museum, invest in a top-notch film scanner. Otherwise, this is pretty good.

Oh - one other factor in my decision was that it was USB 2.0; much faster than USB 1.

Epson uses different model numbers in Japan, but I think the GT-9700F (which I have) = the Perfection 2450. I've been very impressed with it overall and would certainly recommend it if, as Glen says, you don't need museum-quality film scans.

I've been using it with both VueScan and the recent Epson TWAIN driver for Mac OS X.

The FireWire connectivity was part of the draw for me.

i have one since a year now (i think i told you a couple of times about it), and i'm happy. reflective scans via firewire are f'ing fast, 35mm at 2400dpi need a minute or so. full 16bit per channel is great, gives you a lot of room to mess with the picture before converting it to 8bit. i bought mine at dell.com for $230

but since the 2450 is outdated now, i would consider the much better and faster EPSON Perfection 3200 Photo Color Scanner, which you can get for $400

hmm, yes, there is also this thing called resolution: if you buy regular off the shelf 35mm 400 ASA negative films, don't expect them to have more than 2200 DPI resolution, you will see each grain if you scan them at 2400DPI. i have not scanned slides lately, but i don't expect much more. if you want to go into the 3200DPI realm, you have to use 50ASA films. if you scan 6x6cm or 4x5in, you don't need ultra high resolution, 1200DPI should be fine by all means.
(1200 DPI from a 4x5in is good for a 40x50in inkjet printout)

yesyes, the resolution thing. Of course. I try to shoot in 50ASA slide film these days. When shooting negative, my choice is Konica Impresa, when shooting Slides, I try to shoot Fujichrome Velvia 50 and when shooting negative I try to use Konica Impresa 50... But I often end up using the Supra Kodak products, as they somehow seem to survive the scanner at my local photoshop best. Hmm...
Hmm... so you think the Perfection 3200 is going to make me happy... : )
I have this feeling as well... : )
allrighty then... it might be time to put it onto the wishlist.

It says right on the box that it's "perfection." What else do you need to know?