I can't imagine life without a good tube phono preamp. Tubes seem uniquely good at preserving the subtle micro-dynamics that make LPs sound like live music.
Now, about the so-called tube noise. I have to disagree respectfully with some of the posters above. It all depends on the particular design of tube preamp. First of all, I am a big believer in using a stepup transformer for MC cartridges, and this essentially means that even the lowest output MC can be raised in output to MM levels totally noise-free. So we are really talking about the noise level of a moving-magnet tube phono preamp. Here is where the design makes all the difference. Some tube types are much quieter than others. In my main phono, I use a Siemens D3a as the first tube and it is very, very quiet. NOT like your typical 12AX7 or 6DJ8, but inky black quiet. Not to brag, but my tube phono preamp is quieter than any of the solid state phono preamps I have tried which include Threshold FET 10E, Audio Research PH-1, Lehman Black Cube, and Emotive Audio Circa. I realize these transistor units are not the latest megabuck models but still they were each considerably more noisy than my little tube phono using run-of-the-mill tubes purchased on Ebay. Admittedly the D3a is a pretty special low-noise tube but that's my point. Using the proper tube for a sensitive circuit like a phono preamp is the mark of a good design.
That's my rant for the day.