one thing i found recently, and now use constantly, is the docks ability to open files by drag'n'drop (i also realise now this is standard for most os). this is more useful when you can, in your situation, have preview, quicktime, photoshop, safari, IE, firefox etc all in the dock (a useful, tidy place for all your most used apps, that other OS don't have) for all the different uses of your images. browsing - drop it onto preview. proofing - drop it onto QT. Editing - drop it onto photoshop. check for web compatibility - drop it onto the browsers.
also, for icon view in finder, show preferences and set it to show 128x128 icons with file preview turned on - very useful for folders full of images/multimedia. then set this for all folders, and you can easily switch from tidy, browsing-efficient column view, to the intuitive image-finding preview view with a click of the view buttons in finder.
Welcome to MacOS X.
PS, seriously, find ways to use expose other than F9 F10 F11. i have mine set to middle mouse for all windows, and the bottom two hotcorners for show desktop and show application windows. my productivity shot through the roof when i realised i could have 20 windows open and find any in the time it took to think about wanting to get another window. i want that other file. click-whoosh-click. nice. it becomes second nature now to work in photoshop with 5 files and drag and drop between files by throuing the mouse to the left corner and back into play. becomes second nature. amazing, truly why i love OSX.