Good to hear about the chin-up bar, Wanderlust. But I bet if you tried a full body workout, with weights and cardio, you'd be even more amazed at how good you look and feel. Chin-ups would be just one portion of an all-body routine, IMO. For example, you are likely not doing very much at all for your triceps, shoulders or chest muscles with pull-ups. Though lats, back and biceps would get used well. You can pick up a set of weights very cheap today. K-mart, Walmart, Sears etc have both weight sets and or dumbbells. Though a local fitness center works great too... Nowadays I have my own stuff though.
I didn't say I did only chin ups...
Machines suck miserably and are freakin worthless, give me a jumprope for 20 mintues and throw rocks at the tread mill. Triceps, stick my feet on a bartsool out in front of the bar with your hands on the edge and do dips, then backwards with two barstools for a chest press.
Oh...then we have Bowflex Selectec dumbels and a portable bench. Oh, and genuine stairs instead of starmaster, carrying my mountain bike..
I've come to prefer real movements to precribed ones, i.e. machines and the results are incomparable.
But, different people work best with diffferent things. The pull up bar is spreading my back which has always been a weak point and it has made the most difference in how my clothes fit.