Cellphone-reviews just compared the Samsung Omnia II and HTC Diamond2, two of the most popular windows mobile phone in the market today. Now I'm leaning more towards the Diamond2 because of it's really a nice looking phone and based on videos I've seen, it also has a really nice UI.

The author also posted some comparison pictures of the Samsung i908 and the Diamond2. The Samsung i908 seems to trump the Diamond2 in low light pictures but I think I feel like the Diamond2 does a better job in daylight conditions although the author still put it in favor of the i908. Check the link above for the full comparison.