It depends where (area) and how long you will be locking your bike up?

I live and work in a big city where there is tonnes of bike theft everyday so I was extra thorough when looking for a good lock. I ended up purchasing the ABUS U-Lock Granit Futura 64 $140. as my travel lock. The Futura 64 is a super lightweight (2 lbs) 11mm u-lock that is easy to carry and still very secure. I can not reiterate how great this lock is for traveling around the city for hrs stopping here and there to shop, tour, get a bite to eat, see a movie. Everyday kinda stuff
ABUS U-Lock 64/120HB230+TexKF (30147)


I also purchased a Kryptonite KryptoLok Series 2 STD $60. to keep at work 24/7. I am fortunate to have a secure dedicated bike area at work that is caged and locked so I do not need a super heavy duty lock there. The KryptoLok Series 2 is more than enough and very affordable, great bang for the buck U-Lock.
KryptoLok series 2 Standard

At first I was going to go all out and get something like the Kryptonite New York Fahgettaboudit or New York Lock Standard but they were just too heavy to ride around town with for a day. They are amazing locks that will force a thief to look elsewhere but again, the weight was not practical for my use.

If you have the chance to pick up a ABUS U-Lock Granit Futura 64 and compare it to other U-locks on the market try it. Yes, it is expense but the portability + protection is what you are paying for and to me it is worth it. I knew I needed 2 U-Locks. One for a dedicated secure bike area at work. And one for travel. I didn't go expensive hard core for my work lock and put the savings into my travel lock.

These are excellent locks and I recommend them both.

I would also look at the Kryptonite Evolution Mini LITE $100. as a travel lock. At 1.65 lbs it is also very portable.
http://www.kryptonitelock.com/conten...ey/001447.html