For on-the-bike locks, I have these two systems, both are heavy, but the chain is really, really heavy, definitely not something you want to carry around with you. More like you have it on your garage or locker for onsite use. The U-lock, is on the heavy side, but mounts on the bike fine. or you can carry it on the pannier. Just be aware that thieves are actually cutting bikes now, to sell the components, so if it is locked outside, no matter how good a lock, they can still cut the bike....bastards
Abus U-lock (this one I got in '11, so it is pretty recent
http://www.amazon.com/gp/product/B001U885MQ/ref=wms_ohs_product?ie=UTF8&psc=1
OnGuard chain(this one I got in '06, so I don't know if there is any chain-based ones that are a better approach now)
http://www.amazon.com/gp/product/B000FL3EAM/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1
Jeff, is this going to be locked outside or do you have a locker?
For a bike locker I used this one:
Abus Locker Padlock(This one I got in '11) One reviewer on amazon complains about the key being wimpy, I haven't had an issue, but I can see that if you go twisting hard over time it can crap out....
http://www.amazon.com/gp/product/B009S5Y7FM/ref=wms_ohs_product?ie=UTF8&psc=1