You could have done a search - we've covered this about 5 times this week!
I have:-
Romisen RC-N3 Q5 II - very small (same size as your index finger) - uses 1x CR123A batt or 2xAA with the included extender. Very bright(150 lumens / 10watt halogen) and 3hrs runtime on high with just the CR123A or 12hrs on med. Longer run times with the Extender. Auto swicthes from high>med meaning you wont be left in the lurch (or the dark1). This stays in my jacket pocket all the time.
http://www.shiningbeam.com/servlet/t...II-Cree/Detail
Fenix TA30 - This is my camping/all round torch. Still not very big (C size maglightish but thinner) - really bright (225 lumens - same as a 15watt halogen), runs off 3x CR123A batts run time is 3.5/60/115 hours on high/med/low. Can tail stand so you can use it as a lamp with a diffuser. Incredibly tough - lifetime warranty.
http://www.fenixtorch.co.uk/led_torches/fenix_ta30.html
(Discount avail to OCUK members from this store)
MG L-mini II - Size in between the above, 220 lumens, uses a rechargable 18650 lion batt, 3 hrs on high, 8 hours on med, 65 on low. Auto switches from high>low and med>low as well. This is my main bike light with the RC-N3 as backup. An amazing little light but as it's rechargeable only - if it dies you won't be able to buy spare batts from the local offy!
http://www.candlepowerforums.com/vb/...d.php?t=232143
For your application I'd say the TA30 would be good - you're going to want a light with long run time that can take the wind and rain and some hard knocks. It can also use a couple of AA's in an emergency. If you're willing to sacrifice a little run time for a smaller torch then I'd recommend the Fenix TA21.
Get 6 spare CR123's (I doubt you'd use one set, but better safe than sorry) online for $1 each and you're sorted for a whole weekend.
You could also get a fenix headband to mount any of those torches too if you needed to go hands free - i.e. setting up a tent etc. i'd also recommend a red Fenix diffuser for night walking or map reading so as not to destroy your night vision.