newf...you are right...very few isolation moves for the back. I just wanted to put an emphasis on deadlifts and pullups for the back that's all
Newf is right about diet...most people eat 3 times a day, and pack down 800 calories at each meal...which would be about 2,400 calories a day. You'd be far better off eating 400 calories per meal, 6 times a day, for teh same 2,400 calories. It keeps blood sugar levels more stable, and provides a constant source of energy all day long, as well as protien for muscle repair.
(not saying 2,400 calories is a magic number you should consume...just a nice round number for an example)
for definition you need to lose fat. track your diet and find out how many calories you eat every day, grams of protein, fats and carbs consum4ed. I like to use Fitday.com for this so I don't have to write things down...and I'm a computer geek who works at a computer all day long so it's easy for me to update my daily journal.
If you eat 2,800 calories a day now, and aren't losing body fat every week, you should drop 200-400 calories a day, over the course of a few days, stick to that for 2 weeks, and see if you're losing fat then.
As far as getting hungry after working out...you should! You should eat something solid about 90 mins before your workout. assuming your workout is 30-60 mins, that puts you on target to be eating again after workout. I recommend a whey shake or whey + casein if you can afford it (still should be under $1 per serving). Down 30-40g post workout to keep the muscles happy. 60-90 mins after that meal, eat something solid again. You should really eat every 2-3 hours.
And of course, drink lots of water, and take a good multivitamin that contains no fillers or preservatives.