First job out of school? You have just taken your first step into a larger world (of eating).
The issue with a lot of lunch meat is the sodium content. Doesn't matter to me as I don't get much sodium in my other meals. I go for turkey every time though, and not the super-processed stuff. Sliced deli turkey is good. Watch the bread carefully and go for WHOLE wheat bread. Alot of commercial bakeries like to take white bread dough and color it brown, then label it "wheat bread". Read the label. Steer clear of any hydrogenated or partially hydrogenated oils and high-fructose corn syrup. These are diet busters.
As gripstrength suggested, stir-fry and chili make excellent lunches (and easy on the pocket-book).
The in-between-meals-meals depend on your job. If you're strapped for time, a handful of almonds and raisens will do. Protein/carb bars work and take all of one minute to wuff down. I like Luna bars and Builder's bars myself. I avoid anything with maltilol in it though - a wonderful osmotic laxative. The in-between-meals don't have to be big, but they're unquestionably better than going without. If people frown, tell them you get hypoglycemic and have to eat something.
Personally, I like non-fat, low sugar vanilla yogurt with 1/2 cup of blueberries. I buy frozen blueberries which thaw on the way to work (way cheaper than fresh). Another thing I sometimes do before work if I have time is toss the yogurt and berries in a blender with a cup of skim milk, cooked oatmeal, ground flax, whey protein and some crushed ice. Pour that into two little drink containers and there's my morning and afternoon snacks. Tupperware and insulated lunch bags are your friends.
RB