Vintage crank advice
 

I'm thinking of replacing the cranks on my 80's falcon road bike, the left side crank arm rounded out and right now i'm riding with an old mtb crank on that side.

I'd like to replace with something close to the original which was a 170mm Stronglight, I've actually found one on ebay in france for $30 plus $16 shipping

I also did some searches for campy sets and found some that looked pretty nice...
VINTAGE CAMPAGNOLO ATHENA CRANKSET EXCELLENT

What should I do? I would like to stay original but i'm kind of leaning to the campy...

Also Should I/will i need to replace the bottom bracket?

Hello nice looking cranks both of them. the stronglight as you mention will be close to orginal. the 'Athena' crankset is actually a 1'st gen Chorus set. that is one of my favorite crank types. I do not know what type BB you need but I just paid 100 for a Centar as that is the only one that seems to coem in a 111 symetrical

My favorite classic Stronglight cranks are the drilled ringed 104bis and the ever-so-lovely and super light 106 (which is a dead ringer for Campy SR cranks). Those two Stronglight cranks would enhance the looks of any 80's classic bike. I could certainly see both cranks on an 80's Falcon.
Both those models still come up regularly from French Ebay sellers. Only thing with the 106 is, it's 144 BCD ring bolt spacing is starting to be harder to find outside of these french eBay sellers. I went to a "respectable" bike shop in the SF area last year looking for replacement rings for my 106, even if I had to get a non-Stronglight brand ring from them, and the sales people didn't even know that rings come in 144 BCD!

Have you gone Ben's bikes? They are driving to Atlanta buying up bikes. Chances are you wave $40 in their face they will find you something.
http://bensbikesathens.com/

I'm buying new set soon (I am not loving the Ocatalinks on my 98 T700, Like the gearing but they are spaced wide and I think they look like crap). I think the Sugino XD 600's are sweet looking with a classic bike flair and plan to get some as soon as the cash is available. VO has several good looking sets.
http://www.velo-orange.com/cranksets.html

yeah, actually they are the ones that got me back on the road with the mtb crank arm... thanks to them for that... they're good folks.