I'm a fan of Irfanview for viewing and some very basic photo manipulation, but I don't get the Adobe hate in a thread about image editing. Photoshop is indispensable and Lightroom is a really excellent tool for photographers.
You might get a bee in your bonnet like I do when upgrading Adobe "freeware" like Reader and Flash Player, but this doesn't make their good tools less useful.
For the photographers here (since B&W and batch processing were mentioned in the same sentence), I find Bibble Pro really useful for some RAW editing. There is a plugin called Andy that does very nice B&W film simulation, and if you are a licensed NoiseNinja user, it can apply NoiseNinja in RAW conversion, among other useful stuff. These days I really prefer Lightroom for its UI, but Andy B&W keeps me coming back to Bibble.