Lots of good suggestions here so I'll just add to it with my experience. First, I wouldn't buy anything from dick's, from what I've seen it's all cheap quality at a price point that is set too high. Second, if you want good pricing on lightly used premium equipment, then Craigslist is absolutely the way to go. Always someone selling off their home gym equipment. Also keep your eye out for Crossfit gyms closing doors too, might be able to score some awesome stuff for pennies on the dollar. If you've got the budget for it, just go with Rogue or another quality brand.
Here's some items I would be looking for...
If you just want to do general compound lifts such as squats, deadlift, ect. get:
-Barbell (doesn't have to be top of the line for general lifting)
-Squat Rack (I prefer a Yoke for strong man stuff)
-Steel plates (no need for bumpers if you're not doing Crossfit or Oly lifts)
-Rubber mats (only a couple for when/if you do deadlifts)
-Pull-up bar (either built in to your squat rack or stand alone)
-Kettle bells or Dumbbells (at least a couple different sizes)
If you want to do Crossfit-type and oly workouts get:
-Barbell (higher quality that spins freely)
-Squat Rack (I prefer a Yoke for strong man stuff)
-Bumpers & Steel plates (as said above, large bumpers and supplement with smaller plates)
-Rubber mats (space big enough for Oly lifts and CF stuff)
-Pull-up bar (either built in to your squat rack or stand alone)
-Kettle bells (at least a couple different sizes)
-Plyo Box (you can make this yourself pretty easy)
-Wall ball and Target (buy wall ball, make target)
-Jumprope (speed rope such as what Rogue sells)
-Row machine and/or Airdyne (if it's in your budget)
-Bands (for warmup and mobility)
Some extra stuff you could add if you wanted:
-Sandbags (look at Strongfit's version, it's the best and priced well IMO)
-Sled (for pulls and drags)
-Slam Balls or Stones (carries and cleans)