All photos, once shot on either my Minolta DSLR, or iPhone are imported into Adobe Photoshop Lightroom, and in that I do most of my tidying up, cropping, rotation, lighting corrections, resizing etc before outputting directly for the web (awesome program, designed specifically for professional photographers) It also catalogues my entire collection of over 20,000 images (not counting those still on film (negs and slides)).
For the thumbnails (drop shadow, rounded corners, reflection effects etc, I use Picturesque, written by a couple of IT Students for the Apple, and who won a major Apple award for it. A really nice Mac Application – definitely recommended.
For the banner, and where I am doing serious image manipulations, I link out from Photoshop Lightroom into Adobe Photoshop CS4.
All this (including all video editing, and writing this website) happen to be done on a MacBook Pro, but it could equally be done on a PC, (or these days on a Mac emulating a PC!)