Hey I am looking for a new lens to buy before vacation (to Glacier N.P.) . Right now i have a D50 with the 18-55 kit lens, 50mm 1.8, Sigma 70-300 APO, and Tokina 12-24. I like to shoot landscapes and wildlife and airplanes. I was thinking about getting the 55-200vr since my sigma is a little soft, or i was thinking about getting an sb-600. What do you guys think i should get or what other suggestions do you have? I don't mind buying used lenses, and the price limit is $300. PS. what would be a good polarizer for my tokina 12-24?