Most people agree that Adobe Photoshop is the most advanced photo editing software. The new Adobe Photoshop Express 2.0 is now available for free download for iPad. Adobe Photoshop Express offers a simple and interesting way to edit, enhance and improve your photo quality directly from any iDevice such as iPad, iPhone and iPod Touch.
This question is not about using Photoshop but about purchasing Adobe Photoshop. I'm not a full time user of Adobe Photoshop nor a designer, but sometimes I do get jobs which requires me parsing of PSDs into HTML.