I will be in thiland in august and im backpacking for a long time, so i will have a big back pack, and alot of improtant things on me. i will be staying in hostels all the time im travling around but im abit confused as to what i would do with my backpack if i was going out on the night drinking. Would i leave it in the hostel i am in? is that safe?. Would i just take most valuble things with me?. this probly sounds a stupid question but any info will be much apreciated.
You could always stay in a "better class" hostel/hotel, one with a security box to safeguard you valuables - and do not leave the key to that box out in plain sight! Check your doors often, you can put something balanced on the door knob that will make a racket if a door is opened. (Coke can with pebbles or coins in it will do. I always stick my key in the crack over the door, usually it is on a large tag that will fall and make a noise when the door is opened and I am asleep!)
I don't like ground floor rooms or even upper rooms that have a walkway that passes my windows - too much chance there! Choose your cheap hostel with security in mind.
If you get ripped off in a hostel or hotel more than likely it will be by a fellow tourist. Use bags that you can lock with a padlock, this won't stop a thief with a razor knife from getting in but you will recognize that you have been robbed sooner.
Like the previous poster said, keep your valuables to a minimum! There are lots of internet shops all over Thailand, if you planned on taking a laptop - don't, leave it at home. Lots of info can be transferred to a flash drive that is small enough to keep in your pocket.
You can store information on the internet, simply record any info that you need in an email to yourself and save it. You can store flight itineraries, flight reference numbers, telephone numbers, serial numbers of travelers checks - lots of important stuff! Make photocopies of the information page in your passport, you can even scan that page into an email too. Keep the photocopies in different places in your bags. The photocopy of your passport page will help you get a replacement passport at your embassy.
Also, pick your friends carefully! If you get ripped off remember it most likely is by another tourist or someone you allowed into your room! When or if you have "guests" stay over in your room - lock your wallet and stuff up before you take a shower or go to sleep! Better safe than sorry!