Congratulations!
Cannon EOS 60D is one of the finest cameras available today, and the two lenses are superb. You're in for a wonderful experience.
For close-up and macro photography, however, the switch from a compact camera (smaller sensor) to an APS-C format camera (larger sensor) has a down-side: depth of fiels is much shallower with APS-C. The explanation is pure physics, I won't get into details.
Generally, for maximum depth of field, you need to close the aperture as much as possible (higher numers, like 16, 22, etc.). With all-around lenses like your 17-55, f/16 would be the smallest aperture adviceable, because at smaller apertures diffraction starts reducing the overall sharpness (again, the explanation is pure physics). The good news is that
macro lenses are designed especially for being used at the smallest apertures (up to 32 and even 45), thus achieving a maximum depth of field without loosing sharpness.
For large prints, use your DSLR: finer grain, less noise, etc, etc. However, for pictures that will only be published on the web (you don't need very high resolution), a compact camera will give you a significantly better depth of field (which is relatively important for flower close-ups/macro).
You could achieve better depth of field with a DSLR by using a special technique: focus stacking (see:
Focus stacking - Wikipedia, the free encyclopedia and
).
Threaded Mode
