I've been a happy owner of an FZ20 since 12/04. When the FZ30 came out, I was certainly tempted, but for my purposes, I couldn't find enough justification to warrant the cost of upgrading. I suppose if I could sell my FZ20 for a good price, I would consider it, but otherwise I have to agree with Squirl and Ladyhawk.
I have also been interested in trying a DSLR, but found the prices (especially for the lenses to even come close to the capabilities of the FZ's) to be prohibitive. When there didn't appear to be either an FZ40 or a reasonably priced Panasonic DSLR on the horizon, I took the plunge for an Olympus E-500 DSLR. If anyone else is interested in exploring the DSLR format at a reasonable price, you can get the E-500 with two lenses for $699 (after a $100.00 rebate). With the two lenses, it gives you about a 30mm to 300mm (35mm equivalent) range. It still won't match the range of the FZ's, but it does seem like a good way to get introduced to the DSLR world.
That's not to say that I expect the E-500 to replace my FZ20. I still expect to use both in different situations. I also expect that in a year or two, I will probably be looking for an FZ?? to upgrade my 20.
Bottom line though... only you can know if you find enough advantages in the FZ30 to warrant the upgrade at this time. Good luck in whatever you decide.