It really depends on what features are important to you. I compared at the Blackberry website, there is a page there where you can compare the various models.
Here's a link to the BB website BlackBerry
Yes, the 8830 has a media player. After you've compared the features be sure to go and handle the different models, to me the 8830 just felt right.
I forgot to mention that there are rumors that Verizon will be coming out with the curve soon. Check the Verizon forum here for info on that and the way that Verizon is handling GPS on phones that are equipped with it.
The keyboards are very different. The 8830 has the full qwerty version whereas the curve has two letters assigned to each button. I liked the 8830 better because it is bigger. The curve just seemed too small.
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