Which store plugin?

There are so many great looking options, I have having a hard time deciding, which would be the best store plugin for me? I will be selling digital scrapbook supplies and need and instant purchase and download option. The downloads will not be single images, but will be entire files, sometimes multiple files. Is there a plugin that works better with the instant download of large, multiple files? It would also be great if the plugin worked with the themes so that my entire site will be cohesive. I am also looking at many other plugin options, a gallery, forum, membership area, etc, how do I know if certain plugins will work together?

The blog I need help with is creativelyobsessed.wordpress.com (Changing to .org as soon as my host is ready)