Olympus E-300
Hi,
The E-300's a great camera I have been using one for around six months, after selling my FZ-20 on ebay. Both are good camera's, however it all boils down to what you are going to use the camera for.
For decent wildlife photography, forget a digital compact, you really need to start with a DSLR.
For decent bird photography you really do need to be looking at long lenses with wide apertures. Even shooting something the size of a swan using a 400mm zoom lens at a distance of 25 - 30 mtrs will make it look like a golf ball on the horizon.
Maybe that's slightly over the top, but really will need big lenses to get good results (unless your stalking tactics are superb), however remember all is not lost, as the APS-C (Canon EOS & Nikon) sensor size with give you an additional x1.6 to the focal length of the lens by 35mm standards (Olympus x2).
The FZ-20 just isn't going to give you the focal range required (the results are also a little too soft at the telephoto zoom end of the range), you'll only end up dispointed, wishing you had purchased a DSLR in the first place - I did !!
As for the E-300 its a great camera, but you really need to spend decent money on lenses with ED glass to get the best from it - At this point the whole E-system becomes very, very expensive, hindered by a lack of third party manufacturers etc etc.
If I was to start from scratch, I'd consider going down the Canon route with either the 300 or 350D or Nikon, with the D50 or D70. If you chose either of the two I've just mentioned the whole world opens up to you with regards to cheaper optics, Sigma with EX lenses, Canons own lenses are great etc etc.
Many of which can be picked up for the right price on a well known internet auction site, just make sure that when you purchase your lens, they are no more than a couple of years old. Double check with the seller that they'll work with your digital SLR - Some older Sigma lenses won't work unless they have been re-chipped for use with the newer digital camera's (this is so expensive it not worth doing, if in doubt walk away).
Hope this helps.
Regards
Mark