Digital cameras are wonderful. I really did not start shooting until digital really became viable. That said, for digital cameras are essentially very portable and special purpose computers. Computers have a half life of 6 months. They are always being replaced and given their quick turnover, when they fail, they usually are not worth repairing (unless they are VERY expensive).
Can you get around this - with digital bodies - not really. So, what I would do is go with a new Kx and for $30 get a 2 year extended warranty. For a 3 year span, if something goes wrong - they fix it. Will it have the two wheels, and all the controls, no - but through the menu you can do everything. The K7 has this, but at an increased price. As others have written, the K5 is nice but go with a k20 or K7, and put the rest into glass. I really doubt if you can find a K20 new available - so you would need to go with a used one (and the extended warranty would not be available).
What I have done, is when I need a new body, is to buy what is being replaced. When the K7 was announced - the K20 hit $650 - down from its introductory price of some $1300. Yes, it is nice to have the best with all the bells and whistles, but as a professional photographer you are going to need to survive and that means financially - so you need to watch your capital expenditures.
Originally posted by Pentax Kid The K5 is around double the price of the K7 and looking at the comparison: Pentax K-5, K-7, and K20D Compared only real diffrence is 2 more mp 2 more frames per second and better iso.
Is it really worth spending double?
No - go with the K7 - it has everything you need with all the creature comforts - buy the extended warranty and start looking for glass. Craigslist is a good start along with the Marketplace here. Note - e.g., for a 50, get the A 50/1.7 as its fast enough for DoF control, but affordable. The 1.4 and 1.2 are nice but expensive - the 1.2 is VERY expensive.
Lenses - there are several type. The completely manual ones (M42, K and M), and then the semi intelligent A, FA, DA etc. Then the motorized SDM and CD ones. Or what I would classify them as - totally manual, screwdrive and then motorized. Pentax in the past has had some problems with the motorized (SDM) and the new CD are apparently suppose to fix this. The SDM are also the newer faster lenses (both in aperture and focusing speeds).
I have stayed with the fully manual and screwdrive ones, since they are simple. The screwdrive offer autofocusing and also automatic apertures. They are older, usually cheaper (then there are the FA31, FA43 and FA77 Limited lenses - screwdrive but pricey due to superior optics and magical qualities). They also they usually do not fail because of their reliance on very limited electronics.
Hope that helps (by the way - I have two sons in college, so juggling comes with the territory),