Nick Siebers , Mar 02, 2008; 11:13 p.m.
I used one, then two, then three of the K1000s until a week ago when I went digital. I had each of mine cleaned for about $100, I do not know about the lenses though. The M series lenses are built very well in my experience and ones from the 80s are probably fine; newer lenses will fit, but you won't have any of the special functions (auto-focus,etc.) And if you go digital some day, Pentax mount lenses will fit on their digital cameras, so it is a great system to buy into. I haven't used non-Pentax lenses, but you can get M series ones pretty cheap from Adorama, and really cheap from eBay if you don't mind an occasional dud.
If you are just starting taking pictures, this is a GREAT camera, as it will force you to learn about exposure but within a few rolls of film will have you taking pictures that blow any point and shoot out of the water. Put on the standard lens, shoot with the meter needle in the middle, see what happens and have fun!
(Il Duomo shot (K1000 and 28mm M-lens) -- 501 x 768 photo)