A bit about chains, protection etc:
http://lockitt.com/chaininfo.htm


My stealth method, which has worked for the last 10 years:

a) Make bike as ugly and dirty as can be. Seat, handlebars should be the only parts of the bike that will not make you stain your clothes. OK, chain, derailleurs, rims should also be OK.

b) No Shimano, Scott, Giant mambo-jumbo. Take it all off. Tear it off - make it look ugly. If it's an aluminium frame, it won't rust so feel free to peel and damage paint in random places.

c) No shocks, disk brakes and other stuff that scream: "this can be sold on flee market to naive people as high end bicycle". Brakes on your bike can be expensive, but make it road, or v-brake - so they don't draw too much attention. 200 euro v-brakes draw less attention than the cheapest rubish disc brake.

d) Take off your bike anything you want to keep. Anything fancy definitely. I keep my tools and spare tyre in an old, ugly, greasy frame bag, but it just doesn't look like you want to touch it without gloves.

e) Bike should be as cheap as possible, so you don't cry when it does eventualy get stolen. Nice parts for commuting don't have to be expensive. Shimano Acera works just fine and doesn't cost too much, for example. Such bike will not be the lightest and the fastest, but it can be a really good ride. If it is flat - go for singlespeed for several reasons.