Hey Nathan—
Wow… so it looks like we’ve figured it out. Here’s the problem: the error we were getting that said the database table ‘exp_snippets’ already existed? It’s because it already existed.
Ta da!
I can’t be 100% sure of the reasons why, but I strongly suspect it’s because an upgrade had been tried on the database once before, failed for whatever reason, and then rolled back. Now, to get the database back to working order for EE1.x, one would just import the backup, the SQL dump. The problem is that importing the database backup doesn’t remove those new EE2-only tables.
So when the upgrade installer hits an error because it says such and such table already exists, it really means it. I upgraded the sandboxed version of your site, but before I did so, I made sure to remove all the EE2-only tables from the database. Then the upgrade went off without a hitch. For reference, the EE2-only tables that I removed are:
exp_accessories
exp_channel_data
exp_channel_entries_autosave
exp_channel_fields
exp_channel_member_groups
exp_channel_titles
exp_channels
exp_comment_subscriptions
exp_cp_search_index
exp_fieldtypes
exp_layout_publish
exp_snippets
I’m talking with the dev team about how we can improve the installer to avoid this problem, but at the very least, I’ll be adding this information to the upgrade troubleshooting article here.
Give the sandboxed version of your site a go and let me know if everything checks out (after template changes, etc).