To pitch or not to pitch, that is the question

Okay, I've been prattling on about this ongoing issue in numerous different threads, now I just want to directly solicit some opinions.

The situation: I severely underpitched (a single smack pack of Wyeast 3944, no starter) a beer with an OG of 1.086. (I know better now, Mr Malty's and all that) At 7 days, SG was 1.058. At 14 days, it was 1.048. I am now on day 16, and based on airlock activity it is still attenuating -- but clearly it is going dog-slow.

Soliciting opinions: Would you, fellow brewers, a) proactively pitch another pack/starter right now, or b) wait to see if the fermentation actually stalls before taking any further action?

I've never really run into this problem but my initial though is that whatever bad phenloics and esters you are going to get are probably already there. I'd just let them finish the job.

If it's gotten that far already and that quickly, don't worry about it. Leave it for a while and check it later. A beer that big should age a bit anyway and if it was near half of it's OG at 2 weeks you're doing really well. Did you pitch an Activator or a Propagator? If you pitched an Activator you're probably close enough to the cell count, especially if it's fresh (if the manufacturing date is within a couple of weeks of when you used it.).
I sometimes use Propagators for low to regular gravity beers if the yeast is really fresh(they often arrive at my LHBS a day or two after manufacture), and haven't had many problems.(and I think that those were temperature issues) I would definitely suggest making starters, but you can get away with being a lazy brewer. It'll just mean the difference between good and great beer and a relatively long fermentation as opposed to a really quick one.

Let it go til it stops...if it stalls, then re-pitch with a starter

Cool, thanks, sounds like I will stick with my original plan. Somebody made a comment over in the Yeast & Fermentation forum that made me start to second guess myself.

I did use an Activator. And yeah, I was planning on leaving it in the primary for about 6 weeks anyway, so slow fermentation is not really that big of a deal in and of itself.

Thanks!