At first glance, the Canon 35-80mm f/4-5.6 seems like a very average lens, even when compared with other cheap kit lenses. However, if you can look past the plastic mount, slow aperture, and cheap build quality, this lens is by far the best macro lens out there for its price.
A simple modification turns this otherwise ordinary lens into a super-macro lens that works in a similar fashion to the Canon MP-E 65mm. I removed the front sticker, unscrewed 3 retaining screws, and removed the front 3 elements (the AF elements). With these elements removed, the lens is focused by either zooming it in/out or by moving the camera back/forth, just like one would do with the MP-E 65mm 1-5x macro lens. The loss of autofocus is hardly a concern for extreme macro work, since most macro shots (especially at high magnification) are manually focused. The slow aperture range of this lens isn't much of a concern either, since most macro work is done at f/8 and beyond for DoF reasons.
After the mods, I would say that this lens goes from around 1:1.5 magnification to ~2:1 life size magnification. Truly amazing results for something that you can easily get for less than $40 on eBay. Indeed, even dedicated macro lenses can't exceed 1:1 magnification without using extension tubes. And, to make the deal even sweeter, you still get full electronic metering and aperture controls just like you would with any other EF lens, so no stop-down metering is required.
Here is a shot I just took with mine (I saved it at JPEG quality 7 in Photoshop, so there may be some compression artifacts). Click on the bar to see the full-size image.
This shot was taken with the lens at 35mm focal length, which is its LOWEST magnification setting. Zooming the lens out to 80mm will allow the tip of a single ballpoint pen to fill the frame.