So the 17-85 IS is precisely the lens designed to cover the same equivalent focal length as the 28-135 was on a 35mm film camera. On the 30D you have to multiply so the 28-135 gives an 35EFL of 45-216. That IMO is not nearly wide enough for your intended use.
The FZ5 has the 35mm equivalent 36-432mm f2.8-3.3 and that will be tough to match in a DSLR without spending some big money.
The 30D w/28-135 will yield 45-216 f3.5-5.6 so its range is limited at both ends and is dimmer.
The E510 will give a 35mm equiv 28-300mm between f3.5 and f5.6. It is wider, but missing some at the tele end from the FZ5. Its also dimmer.
suggested a setup that is far brighter, covers 27-80mm, but you will not be getting change back from $2000. You would be missing a huge abount in the tele end of things. I'm not a huge fan of the 17-85 Canon lens option. While its not horrible, it does have some issues.
It may be best to invest in something like the E510 and both kit lenses. When you use it awhile and discover your most used range and desire a brighter lens in that range, you will be able to do so and still be cheaper than the 30D option.