Wow, I can already post a suggestion... ;D
I'm using
Leadtools ePrint. I also have an older Acrobat version but in my opinion ePrint is far better for conversion.
It's a driver software that emulates your standard printer (or any printer if you there is more than one) but "prints" the document as about 160 file formats like pdf, jpg as well as differrent vector and document formats. So you are not just able to convert into pdf but also easily convert pdf's or Office documents to graphics in a
very high quality.
Everything that can be printed can be converted as well. My version is IV, the actual one is V. It's not for free but in my opinion it's worth every Cent of the 49$.
After installing, it will appear in the print context menu. Standard resolutions are 150, 300, 600 and 1200 dpi but you can choose a custom resolution as well.
More information and a free trial for download can be found here:
http://www.eprintdriver.com/default.html