Welcome to the TDP forums!

Tough questions. The superzoom lenses (18-250 and similar) do sound nice, but that huge zoom range comes with a host of strings attached, mostly in the IQ department. I think they're worth considering for a one-lens travel solution, but IMO they aren't best for general use. IMO, the best general purpose lens for an APS-C body is the EF-S 17-55mm f/2.8 IS, but it's pricy. A much cheaper alternative with IQ nearly as good is the Tamron 17-50mm f/2.8 non-VC. The EF-S 15-85mm is also excellent, trading a slower aperture for a broader range.

For decent macro capability without a true macro lens, consider a set of Kenko extension tubes for the general purpose zoom. Standard and super zooms that are labeled 'macro' aren't even close, usually.

As for the telephoto lens, quality is generally proportional to price. I use the EF 100-400mm f4.5-5.6L IS for shooting birds, and it's excellent for that. Other options are the 300mm f/4L IS and the 400mm f/5.6 L. The latter is great for flying birds where you need a fast shutter speed, but less so for handheld shots of perched birds, where IS is a big help at those focal lengths. Getting to 500mm with good IQ is expensive, unless you get an older MF lens (which may not be cheaper than the options above anyway).

Hope that helps!

--John