@paulygonemad — You'll be fine with any head you can lift comfortably, afford, and that has at least 500 watts into 4 ohms. Do not get an Ampeg pf-500, which is a notoriously unreliable unit. Yes, put a VT Bass pedal in front of it, if you wish it. Assume you will spend ~$700 on a new head, unless you go used (used you will save about $200 on a $700 head).
The main issue is, IMHO, is
getting a great cabinet or two
that can do the job. It should be 8 ohms so you can add another if you wish. Any top quality 212, 210, or pair of 210, 112, or 115 cabs are a good way to go.
What if you get a cabinet, but don't like it? Fine. Sell it and try another kind. Oh, wait. If you get a combo, you can't just sell the cabinet—you are stuck, so DO NOT GET A COMBO.
There are also a lot of great cabinets from the fEARful, fEARless, AudioKinesis, Fitzmaurice, and Barefaced tribes. Check them out. You can even get a kit for fEARish and Fitzmaurice cabs with all the wood cut, all the drivers, wires, even glue, etc., from these folks:
http://www.speakerhardware.com