what is the most secure bicycle combination lock? Which bicycle lock that is a combination lock (with a code instead of keys) is the most secure device available on the market? 

Of course everything can be broken, and its only a matter of time, but for which combination lock the time to crack it by a potential thief is the highest, without using tools that a thief is very unlikely to use on the street.

Considering that price and weight are not an issue. The only absolute requirement is that its a keyless lock. Is there anything that has an exceptionally good proven track record, preferably something that is being sold for quite some time already with no major vulnerabilities found?



Clarification: as a lot of people instead of applying common sense, made fun of me and spammed the answers with useless non-information, let me define terms used in the question:

The term "price is not an issue" is to be understood as "Price of the lock up to a single fee of 200 EUR (approx. 250 USD) is acceptable.

The term "weight is not an issue" is to be understood as "Mass of the lock up to 3 kg (approx. 6.6 pounds) is acceptable.
I think ABUS is one of the most respectable, perhaps THE most respectable bike-lock manufacturer around. They have even some numbered levels of protection, the higher the level the higher the protection, even agains powertools (because of special steel alloys, and such).

They have some combination padlocks, which seem very interesting. Take a look at these 4-digit (ten thousand possible combinations):


Reinforced padlock
Chain-lock with combination and key
Cable-style lock
Linkage style (this one is awesome)


There are other options in their site, but I think these are the most robust combination ones.

EDIT: just to complement, I think combination locks are a good option for errands, but not for whole-day or part-day parking out of sight. I suppose the OP intends to do so, since he mentions "in the street" and "keyless".

For example, I use to go to the supermarket by bike, and I think a combination would probably demand time enough to open so that someone wouldn't risk an opportunistic theft.

Now for parking at, for example, a train station full of annonimous bikes (none of these parkings in my city, yet), I'd go with the keyed ones, no doubt. A combination one would be an invitation for the thief to earn a bike AND a keyless lock "combo".

As a final thought: does anyone go out without his own home keys? Would a lock key be too much to put together in the home keyring? Well, just a thought!

Hope this helps!