guys.. getting sigma 70-300 apo os or 18-200os better?
or should i straight save up and get 70-300 L f4 ???
i seriously dont know what to choose now. zz

Tripod scratches? At least not for mine. There is soft rubber on the quick removal pad.

when u planing to get it??
let me know, i was told to get tat lens too if aiming for telezoom lens..

Yes and I just found out about it recently. But it is really effective with the pictures I took. I love the camera profiling feature.
You should get a quality UV filter. A decent one could be Hoya UV(N) HMC filter. If you want something better you can look at Hoya Pro-1 Digital UV filter which is roughly double. If you really love this lens and want to spend for the best... then consider B&W MC UV filter. Indisputably the best there is. The multi-coatings are the hardest and is virtually scratch resistant.

Besides protecting the front element, you must also understand that there are other areas unprotected. Since you shoot in dusty areas, there are high possibility that dust could sneak into the barrel cams while you zoom or de-zoom. Also the buttons and controls are not weather-sealed too. The EFS55-250mm IS is not a weather-sealed lens. So protecting the front element is only plays a small part. You should be investing on a weather-sealed L lens if you are doing serious work.

Otherwise, if you only want to protect the front element from scratches, then yes.. a UV filter will do the job. Just don't get cheapo ones that will degrade image quality.

I only know one guy selling B&Ws in ShutterAsia forums. You may check around there.

450D still using 400D AF if i not mistaken which was from 30D
cheapest way to weather seal is use plastic bag, cut one hole for the lens and lock the plastic bag using ur lens hood, another hole for the viewfinder and lock it using the viewfinder rubber frame, saw this in DCM

50 f/1.2L's price almost 17 pcs of 50 f/1.8II's price