Please recommend plugins & theme for project

We are looking for a theme and necessary plug-ins to support our simple website. We are migrating from another CMS.

Our website summary:

1) We have 1 type of membership that is a recurring payment through paypal. There are no other membership types, free or otherwise.

2) Our users MUST associate a twitter account via oAuth. This is in addition to the email address and password used at regular sign-up.

3) Our members maintain a simple user profile with a few custom text only fields.

4) Our front page could be considered a squeeze page. There is no menu for our site. The front page is where we launch our checkout process sending you to PayPal.

There is NO other content, we are basically a 2 page website. There are of course a few minor pages such as the success/failure upon returning from oAuth or PayPal gateways, login, password retrieval, etc. which I am not including in that count.

Can someone from the community point us in the right direction for themes and plugins for this conversion?

Thank you!