The FZ20 and
now the FZ5 are interesting. Can I get quality 8x10 prints from
these cameras without spending a lot of time in front of the
computer?
The answer to your question depends on a lot of factors. FIRST, how good your 35mm skill and your 35mm system are? If you have already had a good 35mm system (e.g., good lenses - not necessary big), the FZ5 and FZ20 would not be able to generate images as good as those from your 35mm system because (1) the lens is not so great compared with a good 35mm long telephoto lens even though it is a Leica, (2) the 5mp sensor does not capture more details than a good high resolution and saturation 35mm slides can (e.g., Kodak E100VS), and (3) the background separation capability of the FZ is definitely far behind what a long telephoto lens can do because of the very small sensor in a FZ camera body. On the other hand, if you don't have the above mentioned system and experience, you will perhaps love any FZ cameras.
SECOND, whether post-processing is needed is up to your digital skill. With 35mm system, you select the lenses and various type of films (e.g., high resolution, fine grain, saturation, high contrast, etc) before you shoot (i.e., pre-visualization). If you have good film-based skill, you can also set various parameters to achieve the same goal. However, since digital is more flexible, we can also do it AFTER shooting (i.e., post-processing). This is sort of equivalent to darkroom skills. In fact, many post-processing techniques come from darkroom skills, and, as a result, your darkroom skills can also help your post-processing task. Strictly speaking, in terms of straight-out-of-camera quality, the FZ cameras are not as good as films; but, one has an extra degree of freedom AFTER the shorts are taken.
8x10 is perhaps the limit of 5mp mid-level digicam straight-of-camera images (i.e., without post-processing).
Do you have to go for digital? Not necessary. You can shoot slides with your 35mm system and scan the selected ones to computer file for post-processing. Good entry level scanner costs much less than a digital camera and can yield a higher resolution. The Minolta DiMAGE SCAN DUAL IV is only $240 and can provide 3200dpi resolution. This resolution is higher than that of the 5mp cameras. For example, a 36x24 slide will be scanned into a 4535x3023 image (i.e., 13mp). After cropping for a 4:3 image, we still have 4030x3023, 12mp! If the slide film being used is of very fine grain, the details recorded is stunning with a $240 scanner, compared with a 5mp camera. See here for the details of this scanner:
http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=310893&is=REG
Of course, each system has its own drawbacks. However, different people will view the "drawbacks" differently. For example, some insist to have a walk-around and light weight camera, and hence the 35mm system is out. It is all your choice.
Hope this helps.
CK
http://www.cs.mtu.edu/~shene/DigiCam
Nikon Coolpix 950/990/995/2500/4500/5700 and Panasonic FZ-10 User Guides