Mike, i don't know what you plan to use the Mac mini FOR, but if you are not doing anything super-intensive processing-wise, i would NOT wait. OK, maybe give it till the end of February to see if this latest rumor is true, but if not, you should just jump in.
Your health is WAY more important, don't you think?
In my case, i wanted to switch to the mini last JULY, and a "knowledgeable source" told me that the refresh was coming "by the end of August, FOR SURE". That was 6-7 months ago, and he's STILL wrong. So, i waited until December. Finally, i could wait no longer and i jumped in (my PC is on its last legs). I did the SSD upgrade, upgraded the RAM to the max and moved the shipped drive to be the second drive (in other words, "the standard upgrade"). I am VERY pleased, my Mini runs MUCH faster, and i am MUCH happier.
My point is that your health is more important. If you look at all the rumors, no one is really saying that the rumored new version will be much more (or any) more powerful, in terms of processing power. It will just be more energy efficient. If you are not doing something super-intense from a processing standpoint, the current mini will do you JUUUUUST fine.
It is working great for me, but i upgraded mine (and you should too). If another mini appeared tomorrow, i would not be bummed about my decision, i would buy a second machine!
Those are my thoughts, don't compromise your health just to have "the latest and greatest".

cheers,
jim.