Faust, "easy milano" is a magazine for expats in Milan; they always have a map at the end of it. Not the greatest and most detailed, but you can download it in PDF format at
http://www.easymilano.it/eng/index.php and see if it's enough for your needs. I kept a ring-bound Berlitz (?) "pocket book" map in my bag when I was living there, you can buy it at a stall by Duomo, or anywhere I guess, for 6 € or something.
Brera is a very nice area, but most of the central city is OK. Just avoid the area around Stazione Centrale...
I think the best place to look for a good, but still reasonably priced hotel would be around Porta Venezia? I'd say it doesn't really matter exactly where you're staying since the city is so compact. Public transportation is excellent and taxis are relatively cheap.
You already have 10 Corso Como on your list, and it really is a must... But don't forget to check out their outlet at Via Tazzoli 3, it's just a few minutes walk from the main store!
Another good outlet is D Magazine at the end of Montenapoleone and Porta Genova (2 different shops, I've only ever been to Montenapoleone)
http://www.dmagazine.it/ Their stock changes constantly, sometimes you find great stuff from CdG, Dior Homme, Margiela and lots of other labels, sometimes nothing but crap...