Thinking of jumping to analog...which turntable?

Given the quality of the rest of your system, it makes sense to invest in a good quality TT / tonearm / cartridge combo. For the money, I don't think you can beat the VPI Scoutmaster, which comes equipped with the JMW-9 unipivot tonearm. The TT, with tonearm, costs $2400 (retail), but if you are comfortable spending a bit more, then you should seriously consider adding the clamping ring (another $600, but well worth the money).

Some good moderately-priced cartridge choices include the Shelter 501, Grado Sonata, Sumiko Blackbird, and DynaVector Diamond 17D (although this is a very low output MC model, so you might need a step-up transformer).

Agree with Sdcampbell on this recommendation. You'll still need to add a phonostage, so this leaves room to make a serious investment in that critical part of the analog chain. Assuming you make a good choice in the phonostage, you will have a very good analog front-end that will be very complementary to the quality of your digital.
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Gentlemen, thank you both for your comments. But I think I should rephrase the question a little bit: given my current digital setup, what would be the minimum investment in analog (phono stage, analog front end) that would provide a significant improvement over my digital. I am willing to experiment with analog if that number is not too high, yet if I need 6-7K to improve upon the sound, then I may need to wait longer to make the analog investment.

For $1000 to $1200 you should be able to get a nice used VPI HW-19jr table with a good arm (JMW, SME) and a decent cartridge. Don't worry so much about which ones for now. There's a lot of personal preference involved ultimately, and you'll have to experiment later if you decide vinyl is for you.
You may be shocked at how well any reasonable analog setup competes with digital.

If the sound from something like this isn't at least in the ballpark, then analog may not be for you. And you can resell for what you paid very easily.