Help choosing WP theme

Hello everyone,

New WPMU member losing my post virg****... virginity. Anyway, I'm looking to transform my blog into a more interactive community with Q&A section and possibly also forums and in the process rewamping the design on my site.

Before pulling the trigger, I wanted to ping the forums for some expert advice. One concern I noticd popping quite often is that many themes don't play nice with WPMU plugins, because the themes don't follow WP standards but have their own way of working. I wanted to ask how big of a headache non-standard themes are? Do they really cause a lot of headaches? And should I pay attention to getting a theme that's WP standard compliant?

I also wanted to ask theme suggestions. I found a good HTML template that more or less captures everything I want:

http://thememotive.com/multipurpose/landing-page.html

They don't have a WP version for that.

So here's my dilemma. How can I get a WP site that looks more or less like that HTML template AND that plays nice with WPMU plugins AND is responsive? I browsed through WPMU themes and they leave a lot of be desired when it comes to looks, and most of them aren't even responsive.

I was thinking I could create a child theme for TwentyTwelve, but that's a lot of work and my WP skills leave a lot to be desired.

Any advice on how to proceed here? Does anyone know any themes that would fulfill the requirements? Anyone know where I could get that HTML template turned into a WP theme?

Thanks a lot for your help!