Hi Ez
from my observations (or rather, observations of their observations), the bits that most catch the eyes of the ladies are (1) bum and (2) lats, and so your best return-for-effort will come from working on these bits.
For (1), if you can, use a StairMaster machine. I used this for a warm-up, for 15-20 mins, whenever I went to the gym. Put the resistance up high, and really push it, at least for bursts.
Now, I lift at home, and don't have a StairMaster, so squats does the job, but it's harder work.
If you can, do StairMaster AND squats AND leg-presses (another thing that I can't do now at home).
For lats, do chin-ups if you can; if not, build up your strength with lat pull-downs until you can manage chin-ups.
The bum (and to a lesser extent, the lats) are bits you can't easily see yourself in the mirror, unlike the chest and arms. However, that's what the girls check out.
Generally, especially for a newbie, doing chest exercises is the thing you'll like doing most, and doing legs will be the least fun, with back in-between. If this is the case for you, I'd suggest doing the legs first in each workout, and then 'rewarding yourself' with doing bench presses or whatever after that.