Like most, I use Photoshop, but there's an issue with it and it looks like I need to get some new software. PS is ludicrously expensive, and I'm not so sure it's worth it. I know it's industry standard, but we're not really "industry". For this type of work I think you need something a bit more, dunno really, modern? adventurous? I've always wanted to work more with images which blend with backgrounds, such as a face reflected in a pool with Koi swimming round. I know you can do it in PS, but I've never found it works that well, and it's certainly not easy.
NIK was one I looked at, but does anyone have any experience of any others?