Remember that for a 100 mm lens, the working distant is not so close. You may need a tripod.
Samples, click on ALL SIZES to see a larger one:
Canon 100 mm f 2.8 macro (Canon 5D--full frame)
http://www.flickr.com/photos/little_pooky/2500999694/
http://www.flickr.com/photos/little_pooky/2333379801/
This one is 1:1 http://www.flickr.com/photos/little_pooky/2333377673/
http://www.flickr.com/photos/little_pooky/2334206454/
It is good for every day portrait, too. It will be quite "long" on cropped sensor (165 mm) though. You can see it is very sharp.
http://www.flickr.com/photos/little_pooky/2494382012/
http://www.flickr.com/photos/little_pooky/2294503848/
http://www.flickr.com/photos/little_pooky/2168941423/