I would personally go for any 17" screens that have a max res of 1280 x 1024 as the max res that the matrox adapter can handle is 3840 x 1024 so if you got monitors capable of higher res that would push up the costs with little benefit. Matrox have their desktop utility which allows you to maximise programs to fit each screen, without this, when you maximise a program it would spread across the three screens. It's similar to dual desktop but with three screens, a program will reopen in the screen it was last used in. I've kept my 24" dell and at the moment my Mach is hooked up to it. Sometimes you just want to have really hi res, plus not all programes are supported, those that are not, you just have to run them at 1280 x 1024 on the middle screen, the other two screens then go into sleep mode. You could always hook up your 24" dell as a second screen

as windows sees your tripple screen setup as one whopping 3840 x 1024 screen, I haven't tried this but it should work just like dual desktop.
At the end of the day this setup is good for both work and play. During the course of my work I often need to have many programs open at the same time and it helps if I can see them all at once! (well thats the excuse I give the wife :shhh
If you want more info Mav check out the link to the widescreen forums I posted earlier, theres plenty more info there.
P.S Even the Serene screen Aquarium screen saver is real pleasure to watch as the fish swim across the three screens! It's like being at the London aquariums, not too sure what the srimps think below though, shrimp being the staple diet of fish
