Digital cameras forum: how important is weather sealing?

My body and lens do not have weathersealing, but I don't take it in the conditions you will. I would buy one if I were you. If your worried about price, then take a look at the new Pentax cameras, they are all weathersealed. The K20 was rated very highly in reviews. I never pimp out Pentax, but this might be a good choice for you.

Here's a review of the K20
http://www.dpreview.com/reviews/pentaxk20d/

About a few week back, I shot my 1Ds mark III out in the rain for H.R.H princess's funeral. The location was near the grand palace in Bangkok where the humidity is really awful during the monsoon. Even thought the camera worked fine, my L-lenses couldn't bear the humidity. I ended up putting my equipment in my camera's case after the humidity caused so much vapor all over my lenses. No matter how good the camera's weather proof is, there always are some limits.

The better alternative ? You can instead spend for a $10-20 camera's rainsleeve. That really serve your purpose for shooting out whether it's raining, humid, and dusty environment. The design, I bought, is to cover a DSRL camera with 70-200mm lense along with a hug-up flash, and able to mounting on a tripod. That will even save your money to spend on a weatherproof DSLR camera.

Good luck.

You can never go wrong in protecting your gear, from simple plastic wrap to full on water tight blimps. I have had old 35mm cameras freeze because of the humidity inside of the body compared to the outside air temp. Digital gear is no better when it comes to weather proofing some folks have good luck with their stuff mine always seems to fog up when going from warm to cold. I would invest in the best you can buy simply because it will save you alot of headaches and time waiting on your camera to warm up or in my case thaw out.
Great shooting and good luck.

First off, I should say, that I am a dual-system user, with extensive Nikon and Olympus gear. You situation is exactly, where I would choose Olympus above anything else. The reason I decided to put in my $0.02 here, is because I not only own the cameras you mentioned, but have been living in Asia for 2 years already, traveling extensively as well.

As far as DSLR bodies, I currently own (and therefore have a lot of experience with) the D700 full-frame, D300, and D90 DX cameras, and 2 Olympus bodies: E3 and E-510.

You have been considering the D300 only, which has a very limited weather-sealing compared to my Olympus E-3. The D-300 withstands dust and moisture just fine, but I still need to run for cover if ever caught in rain. The bigger problem however is your choice of the 18-200 zoom, which has absolutely no sealing !! The lens is just as important - if not more - to be sealed, as the camera if you ever expect to be shooting in inclement weather. The Nikkor super-zoom is very prone to dust and moisture issues, and since it is not sealed around the mount either, it kind of makes no sense to go for the D300 at all.

Unless you are heavily "invested" in Nikon gear already, for your purposes, honestly I would get an Oly E-3 with a matching weather-sealed 12-60 SWD zoom (24-120mm equiv.) and have the best travel setup. You can shoot in heavy rain, with no worries at all. I know, I have done it ....

Yeah, that definitely makes a heck of a lot of sense, and I can judge from the consensus alone that a weather sealed model is a must.

I checked out the recommended Olympus, it looks nice for sure, but it doesn't seem to be a great low-light shooter, which is pretty important for my purposes.

I've done a lot of research, I like the d300's feature set and more, but apparently the lens I had in mind is a liability. How does one go about finding good, weather sealed lenses? It seems to be a more uncommon feature, at least with nikon, which seems odd considering the brand's unfortunate use of lens image stabilization.