If you're asking about a handheld flashlight for exploring during daytime, I like the UK SL4 because it has a very tight beam, and during daylight you're only going to see the beam center anyway. Not sure of lumens rating, but it's decently high for a single emitter light. It uses 4 C cells and gets good battery life, since being regulated it can draw them down farther than was common with incandescent bulbs. The SL4 L1 is a good model, and can sometimes be found for around $80. It was recently superceded by the SL4 Mk2, but I don't think there's much difference.
If you don't mind Li-ion rechargeable batteries, there are other options also having a tight beam for daytime highlighting.