Moving Website From .co.uk To .com

Hi

I run a reasonably successful article directory with a .co.uk TLD. I have now purchased the .com from the owner. The .co.uk has a pagerank of 3, and the .com a pagerank of 1 (although a year or two ag it was PR5).

My question is, is it better to retain the .co.uk name as primary and redirect the .com to it or should I just bite the bullet and use the .com as primary?

Regards
Steve