Yes, and I like it! Mostly Velvia, but also some black & white. Actually use it a lot, even now (Pentax 645nII and a bunch of lenses). But with the convenience of digital picture taking and processing, I'm using my DSLR more and more these days (Canon EOS 5D MII).

If you like using square filters, like Cokin, try some SINGH-RAY filters. They're all good quality glass filters and instead of using a filter-holder, Guffer Tape works excellent (this way you can stack multiple filters in different angles all at the same time). There not cheap by any means, but you can use the same filter for all your lenses.
Greetings,
Stephan

I've made a few bucks using Hassie's and Large Format Cameras. But that was long time ago when I worked as a Graphic Designer in Germany. Now its just a hobby.

Hi again,
just to add to the list, the new DFA 55mm f/2.8 . This lens will not autofocus on the 645n nor 645nII, because it's a new design that has the autofocus motor in the lens itself.

Hi Willie,
the "crop factor" will be 1.27 for 645 lenses. For comparison it'll be a 0.79 crop factor for 35mm.
Greetings,
Stephan

Hi Kris,
"crop factor" will be 1.27 for 645 lenses. For comparison it would be 0.79 for 35mm. The "old" 645 lenses will not be able to show the full potential of the new sensor and only focus manually. I don't expect the prices on those to go up all that much. I would want mostly the new lenses designed especially for this camera.
Greetings,
Stephan Peters

Hi and welcome,
I have to agree with Kris as well. I would'nt sell it for that price. You could use it just for slides and have scans made as well. There's still nothing quite like a slide show on a big screen. For scans, you should check out Scan Cafe. Their prices are very low and the quality is very good, highly recommended.
Greetings from Idaho,
Stephan Peters

Hi,
I use the Epson Stylus Pro 3880 and absolutely love it. It prints 17 x 22 but you can extend it to 17 x 37.5 inches. Never seen any better color from any printer and the black & white prints are just as stunning. Only drawback, it's not cheap - $ 1200.- But I have never regret spending the money on it.

Hi Rolart,
here's the list, enjoy:
SMC Pentax-A 645 35mm f/3.5
SMC Pentax-FA 645 35mm f/3.5 AL(IF) - new optical design
SMC Pentax-A and FA 645 45mm f/2.8
SMC Pentax-A 645 55mm f/2.8
SMC Pentax-A and FA 645 75mm f/2.8
SMC Pentax-A 645 LS 75mm f/2.8
SMC Pentax-A and FA 645 MACRO 120mm f/4
SMC Pentax-A 645 LS 135mm f/4
SMC Pentax-A 645 150mm f/3.5
SMC Pentax-FA 645 150mm f/2.8 IF - new optical design
SMC Pentax-A and FA 645 300mm f/5.6 ED(IF)
SMC Pentax-A and FA*645 300mm f/4 ED(IF)
SMC Pentax-A and FA 645 400mm f/5.6 ED(IF)
SMC Pentax-A*645 600mm f/5.6 ED(IF)
SMC Pentax-A and FA 645 33-55mm f/4.5 AL
SMC Pentax-A and FA 645 45-85mm f/4.5
SMC Pentax-A and FA 645 55-110mm f/5.6
SMC Pentax-A and FA 645 80-160mm f/4.5
SMC Pentax-A and FA 645 150-300mm f/5.6 ED(IF)

Hi, I have to second John Riley on this one. You should try to find a dealer that let's you do just that. Only then can you decide if it's worth the investment. I use a 645nII and use the lenses on my DSLR as well. Bought a cheap adapter from FotoDiox ($65) and love the results, but there are exceptions. All the lenses are doing fine on my DSLR, very nice contrast and sharp throughout the corners. Then there is the 645 FA 120mm /f4 macro, a lens I hoped would do equally well, but proved to be quite a dissapointment. There's strong color fringing and the sharpness is nothing to brag about. But this lens is doing well on my 645. Why this lens is acting so different than the others, I don't know. So if you have your eye set on a particular lens, only a real world try can give you the right answer here.