I'm currently experimenting with a set of Elixirs on the Lowden. Polywebs - didn't like Nanowebs at all. They sound OK, but see how it goes.
Before that, I've been using Newtones for a few years on it. I think Newtone wound strings are *the* best thing I've heard. My Hathway octave mando came with Newtones too, and sounds great.
One thing I don't like with Newtones is the unwound strings - I just don't find they have the same depth to them. Maybe it's just the way I play them. :-/ But I prefer the unwound strings from the Martin Fingerpicker sets - they've got more "zing" to them. Sadly I don't know where you'd get singles of those from.
(Incidentally, the Martin Fingerpicker ones are so resonant that they turn a Lowden's sound into an over-resonant mush. Which I think says something about the sound of new Martins if they need strings like that, but YMMV. ;-)