You have a terrible OCD disorder that keeps you from being happy with a single camera brand or camera, and you constantly have to keep buying more?
Just like how I have a Canon Digital Rebel XTi that I want to keep so badly and get lenses for, but I have a Pentax *ist DS that I want to upgrade to a K100D and get lenses for so bad. I honestly don't know what to do. The only problem is that I can only afford lenses for one of them.
The answer is simple: get the pentax and lenses.
Sell the Rebel - it will help you with the new camera purchase and/or lenses and once it's gone, the hitch will be gone too.
Make the *ist DS your second/backup camera... (better then having one pentax is to have two pentax cameras!), and you can now concentrate into just one glass system... for both your cameras! He… he…
1) Start working multiple jobs or make more money in your current job so you can afford to buy cameras and lenses for multiple systems
2) Pick one system and stick to it (Pentax, Canon, whatever you pick, just stick to one system). Sell the rest.
3) Learn to be happy with whatever you've got.
As a multiple system user I can tell you that every brand of camera and lenses has advantages and disadvantages ... but it's ultimately what you do with the gear that matters more than the brand name.