I'm considering getting some better quality photo editing software. I was told by a really good portrait photographer that good editing software is a much for a digital photographer besides quality lens. She highly recommended Adobe Photoshop CS4 but I'm operating on a college student budget and I cannot afford to shell out $500 on photo editing software. Does anyone know of any good low cost (less than $250) alternatives to Photoshop CS4 or should I just bite the bullet and pay $500 for Photoshop? I'm currently using Picasa and I find the tools there are quite limiting.