Pentax K-x or Canon 550D?

Hey all, I thought I would ask this question here and see if anyone posts anything that I may have missed. I use a Canon 5DII, my wife also is showing an interest in photography and enjoys using mine. So, I'm thinking of getting a dslr for her for either her birthday or our anniversary in May. Right now I'm considering either the Pentax K-x or the newly announced Canon 550D. I personally think the Pentax K-x is the best entry level camera on the market by far in terms of features, performance, size etc. On the other hand though, if I got her another canon she would be able to use some of my glass. The Pentax K-x is going for about $568 for the body only and I would purchase separate optics, the Canon 550D is going for about $800 for the body only. Either way I probably would need to buy her at least one all purpose lens even if she did want to use some of mine.

What are your thoughts? Any particular benefits to one or the other that I'm missing?
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