7D, D7000, K-5 or SLT-A77 - which one to buy?

I've been a very enthusiastic photographer for several years now utilizing as of late the PowerShot SX 30IS. I mainly shoot wildlife, landscapes and holiday pictures for the family.

I like to make the plunge and purchase a DSLR mainly to allow faster speeds when shooting wildlife and birds. From what I read thus far I think any of these cameras would be a good start with a couple of good lenses, though I would like some advice before purchasing.

Many thanks up front for any and all help.