If you've just started to venture into photography, then it's highly advised you start off with a compact. If you want to jump.. you can get a prosumer, but you should not get a DSLR as a start to photography.

For compact cameras, you can choose any. Just cut your budget by a lot.

For prosumer, it's highly advised to get a Panasonic Lumix LX3. King of all the digital cameras.

But, if you still want a DSLR, then get the Nikon D60/D80 or the EOS-1000D. These are the best of the pick - since your budget allows the purchase of the above.

I think TheWandererX threw too much advice to you and it became saturated.
Lemme try and make it simple.
If you're looking to save 1000-1500 from buying a 2nd hand DSLR, you might just as well forget about it. DSLRs dont depreciate so fast
DSLRs are quite versatile. They have a very decent operating temperature range, yes, even the entry level models. I've read reviews of DSLRs tested in -20 Celsius and it worked fine. So Mount Kinabalu is really nothing, the only thing you have to worry about is battery life. As the temperature decreases, so does the battery life. And another thing, Mount Kinabalu ain't humid, it's just colder.

Olympus Four Thirds System eh. The name really explains it all. The size of the image sensor has a 4:3 ratio and Olympus cameras have a 2.0x crop factor. Just for comparison, Canon's has 1.6x while Nikon has 1.5x crop factor. Now there's no good or bad with crop factors.

Lens focus by wire. This is more commonly known as cable release. Note that to obtain very sharp pictures, the camera has to remain totally still while the picture is taken. And, when one presses the shutter button on the camera, there will be a slight shake. This is where cable release comes in. Basically, a cable release trigger is connected to the camera. To trigger the shutter, you just press a button on the trigger. This way your hands are not physically on the camera, eliminating motion caused by handshake.

RM1000-2000 is quite enough for an entry-level set.

E-420 is RM2k for kit, if I'm not wrong, the E-520 is much more expensive. I'd recommend you to go with the D60 or the 1000D as these are the best of their range. Also, it'll help you later when you want to change camera bodies and have the lenses. All EF lenses are compatible with any model, and EF-S lenses can be used on APS-C size sensors. Nikon has a similar set up. Olympus and Sony are kinda newbies to the DSLR market so it isn't recommended to get them just yet.

IS is in lens for the lenses I think.

Anyway, Zuiko lens is EXTREMELY unpopular. Even Olympus DSLR users opt for other 3rd party lenses like Sigma or Tamron because of the unavailability of lenses, and they aren't as good compared to the Canon or Nikon lenses, that's why we recommend you to get a D60 or a 1000D.

Olympus is an ok-ok brand for digital cameras, but a no-no for DSLRs.

The same answer applies to this question. Why are Nike or Adidas products more expensive than other brands? It's not because their products are better, it might or might not be better than other brands. It's because Nikon is already an established brand in the market. Therefore their brand alone commands a higher price. You're actually paying for the brand when you purchase a Nikon or Canon camera.

There is no "best" brand in the market. Each brand has its own pros and cons. Canon and Nikon for example, have excellent reputation in their image quality, while Sony, Pentax and Olympus have in-body stabilization. Not that I'm not implying that Sony or Pentax or Olympus' image quality is bad.

For your budget, there are a few DSLRs in the current market, I'll mention a few that I know the price.
Canon 1000D - RM1.9k
Nikon D60 - RM1.8k
Sony A200 - RM1.5k
Sony A350 - RM1.9k

Sony also has their own lens lineup. Contrary to what you think that Sony is a newbie to the DSLR market, Sony has actually bought over Konica Minolta, and Sony DSLRs can be fitted with Konica Minolta lenses. This being said, it's good to note that Konica Minolta was already in the SLR market since 1985. And that's also 2 years before Canon introduced its EF mount system.
Along with Canon's EF-S lenses, Sony has it's DT lenses too for digital SLRs. .......

Although still a decent camera, I personally think that the D40 is definitely outdated.
The D60 kit is about a few hundred bucks more than the D40 kit. For that few hundred bucks, you get 4 million more pixels, Image stabilization and a slightly faster burst rate.
If you're comparing the D40 and the 1000D, I'd say that the Canon wins in technical terms.
But if you're budget is limiting you to the price range of the D40, why not consider the Sony A200? Its price is around that of the D40 and the A200 is a very very good DSLR with In-body Image stabilization and 10MP.

...... For the Canon....best of luck to you

Canon camera doesnt have any shutter count checking feature within the camera while Nikon does.
I've heard of a 3rd party software that you could use to check the shutter count, but then again you'd need a laptop with you when you purchase the camera, and that's er, inconvenient?

450d's price inflated? Hmm..seems like 1000d is more worthy.
TheWandererX, I see that you are using a 1000d, how is it? You don't plan to upgrade the body anymore?
Because I saw you bought a few lenses already. Oh ya, by the way, you are using Nissin speedlite, is it cheaper?