1) Well you could get whatever phone is the most expensive and sell (as suggested).

2) You can try one of those phones and see if you might want to switch (Desire is great and many hacks for it, basically a smaller HD2 with trackpad)
(HD2 does WM6, WP7, Froyo but a bit rough on the edges)
(Blackberry eww)

3) Try to "push" the insurance claim into giving you a better phone (suggest the HTC Desire Z/G2 because that is a good qwerty upgrade which now has been hacked ... use the qwerty and froyo as comparison to the N900)
(They may suggest a Milestone, which your screwed cause it is an equivalent phone which has 1 current major drawback = locked bootloader, great phone nonetheless)