I'll agree with ToddR, those SC-T's are a bargain. I just bought a pair of these myself last night, and I wouldn't have done that if I didn't like them. Another old standby is Studio Projects C4s.
Nothing inherently wrong with CK-1's. I just don't consider them a huge step up from what you have, unless you send them to Busman for upgrade, and then you are over your budget.
The folly of asking us for opinions on mics is like asking a bunch of friends "what kind of ice cream should I get". You will get a bunch of answers what WE like, not necessarily what YOU like.
You best friend is you own ears and spending an evening or two listening to lots of samples on archive.org, preferably with those mics running into the same preamp you have.