I'll echo what 7k7k99 said. I just recieved each of the fenix lights from fenix-store, they're pretty nice.

I personally like the P1 the best, it's one of the smallest CR123 lights I've ever seen. I used to carry the arc-LS, but the P1 just blows it away. Too bad it doesn't use a common battery.

But if you want to go with standard batteries, which i assume means AAA or AA, the other fenix lights are great.
The LOP is slightly larger than the ARC-AAA, but puts out a lot more light. I used to have an arc-AAA, but it just wasn't bright enough most of the time. Even though it has a long runtime, I really don't use a keychain light for really long periods, so it was replaced with a photon clone which gave the same amount of light in a much smaller package. I also never really liked AAA lights, they're not small enough to be considered tiny (like a photon), and for just a little more size you can step up to AA and get a lot more power and runtime. Plus AAA's are usually more expensive than AA's, which is one of the reasons for going with a common battery in the first place.

The L1T would be my replacement EDC light, but it's a little too big to carry on my keys. But the fact that it has 2 light levels makes it really useful, because you can choose between a bright light or a long runtime. If you don't mind the size of AA, it's a great light