A lot depends what apps you want to run

- In the UK Any Nokia S60 device can be a good bet due to free navigation

in US (not sure in UK yet) google maps on the HTC desire is astonishing. really really good. The comparison against current N900 ovi maps is rather depressing. N900 also misses out in not having a compass.

The other app I really miss is gravity (or a variety of iphone twitter apps). We still unfortunately don't yet IMO have a "great" implementation. witter is best so far. tweego popped up and looks prettier but is somewhat stalled in features.