The Ducati Monster List web site (http://www.ducatimonster.org/) is full of interesting chatter about riding and modifying monsters. It has one unpleasant side effect though - if you spend even a few minutes on the site you tend to get excited about making changes to the bike. Things that you previously didn't even notice, now really really bug you. The #emissions_cannister for example

Spare parts catalog - http://www.ducati.com/bikes/catalogs.jhtml;MY=2002

Hacks

suspension

BCM Ducati in Laconia, NH has a guy named "Eric" that's a suspension guru. He rebuilt my forks and they're vastly better than stock.

http://www.computrackboston.com/ - local place that does suspension setup/upgrades

reflectors

Everyone removes the reflectors from the front forks. I hadn't noticed until I read about it, and then sure enough they started to bug me. They're nasty little plastic things stuck on with double-sided tape. They're clearly tacked on at the last minute to meet some regulation or other. The good news is that they're easy to remove with a hair dryer and a little elbow grease. One almost fell off, the other needed a little convincing with a screwdriver. Afterwards the forks needed a little cleanup with some alcohol to get rid of the crusty glue that the adhesive tape had left behind.

gas tank stickers

Again, a little heat with a hair dryer and some careful peeling got the two gas tank stickers up. A better idea than the hair dryer is to just leave the bike in the sun for an hour or two - I'd bet this will heat the tank more than the hair dryer.

I stuck the stickers on the inside cover of my owner's manual just so I have them for reference.

emissions cannister

Purely cosmetic, but it's surprising how much better it looks when it's done.

http://www.ducatimonster.org/faq/faq_emissions.html

http://pg.photos.yahoo.com/ph/jerseyjeffshinn/album?.dir=c233&.src=ph&store=&prodid=&.done=http%3a//pg.photos.yahoo.com/ph/jerseyjeffshinn/my_photos

exhaust

You can hack on the stock exhausts to make them louder: http://home.earthlink.net/~desmoduck/muffler_mod.html

Or you can pay someone to do it: http://www.ducatipipemod.com/. I went this route (got the "1/2 mod") and it's amazing how much of a difference it makes. It's a little louder (but not obnoxiously loud) but the sound is magnificent. Not as deep as a Termignioni or Arrow but great value for the money.

rear brake

http://www.tcmproducts.com/Ducati_Rotors.html will drill lots of holes in your rear brake rotor to make it lighter.
http://forums.13x.com/showthread.php?t=117260 - another shop that does the same thing.

Mirrors

http://www.dual-star.com/index2/Equipment/adjustable_mirror1.htm - inexpensive, mounts on the handlebar. Pix on a monster at http://www.ducatimonster.org/smf/index.php/topic,8750.0.html .

http://www.constructorsrg.com/products.html - expensive but very high quality. I've got 'em, they work great and are beautifully made.

Turn Signals

http://www.custombike.org/shock_racing_marker_lights.htm - LED's, about $25. Some talk that they're not very durable.

http://www.cyclegear.com/spgm.cfm?L1=3&L2=&L3=&L4=&item=MRX_OI1_G - look like OEM, but smaller. Bulbs.

http://www.ducatimonster.org/smf/index.php/topic,45863.0.html - yoyodyne LED blinkers.

LED's

See http://www.ducatimonster.org/smf/index.php/topic,43001.0.html

http://www.customdynamics.com/flex_led_array.htm

Horn

You can never be too loud.

http://www.ridesafer.com/page/mfc0/Home.html
http://adventurersworkshop.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=AWI&Category_Code=Stebel_Air_Horns

License Plate Lights

http://www.watsendesign.com/products/current/LEDPLATELIGHT/index.html
http://www.4strokesonly.com/LicensePlateLights.html

Light modulator

Blink your headlight and brake light for better visibility: http://www.kisantech.com/

Cool Paint

http://www.frostysfinishes.com/ - guy in NH that does some amazing stuff with paint.

Custom Fabrication

http://www.arcfabrication.com/ - not sure what's in the water up there in NH but whatever it is causes folks to do some seriously cool custom work. I saw this guy's work in person at the BCM open house and it blew me away. The exhausts are amazingly complex but look and sound awesome.

Track Days

I'd like to ride the duc on a track sometime.

http://www.tonystrackdays.com/ - program for beginners, sounds good.
http://www.nesba.com/ - a group that runs track days. Has a free "intro" session where you can ride for a couple of sessions in the morning.
http://www.teamdaemon.com/ - two track days a year at Loudon.
http://www.penguinracing.com/ - more focussed on instruction.