I recommend you purchase the Columns, then post your findings on here 'cos I have the same set up as you and am also interested in upgrading to the Columns
Have you auditioned the columns yet? Did you read the review of them in the Febraury edition of Gramaphone magazine? They got a good write up, esepecially since they were reviwed only as a stereo pair for music - as such they were described as a special pair of speakers for the price.
I had a look at a set last weekend but have not auditioned them yet. I'd be surprised if they were really a great imrovement, since the drivers are the same as in the satellites and are effectively like a pair of centres in floor standing cabinets, so the cabinets would need to be adding a lot to the sound. The guy in the shop who'd been running them in said they were 'rather wonderful' though. They looked quite good and were nice and slim, but I didn't think much of the plastic bases.