Yeah, I'm looking hard at VS1's- there seems to be a near consensus that it's a good starter gun.
Very true. Alot of beginners, as well as people that come back to paintball after some time, start off with a Spyder. Most times, it's the VS1.
I'm also considering a JT Protium (haven't heard much about it, but what I have heard has been positive-- anyone here have an opinion?) for $60(!) on Actionvillage, as well as a Dye Proto SLG for $190 on eBay. I'm confident that the Dye is a good gun, but I would LOVE to not spend a ton of money right now, and could use the rest for good accessories.
People have different opinions about the SLG. I have never used it nor seen it used, so I couldn't tell you much. I've never even heard of the Protium, but remember that you do get what you pay for. I would definately try to save some of the money for paint, fees, accessories etc.
What do you guys recommend in terms of hoppers (I've heard good things about halos, but that's all I know), tanks (how big of a tank do I need?), and masks?
I wouldn't get a HALO in your position. I have mixed feelings about the Halo, but that's just me. I'd suggest a VLocity Jr. - it's a great hopper, but not too cheap at $97. I personally have an EGG3 (Viewloader EVLution 3), but I didn't buy it (got it for free from a friend that works for a paintball company). If I had the choice, I would have chosed the VL Jr.
In terms of masks, just find one that you feel is comfortable. Always make sure they have anti-fog or (preferrably) thermal lenses (not the same thing). I got a Dye I3 Pro from ZephyrPaintball.com for $60, but again it depends on what feels best to you - comfort is very important. I'm sure your local shop has a lot of masks that you can check out.
In terms of tanks, it depends if you're willing to shell out the extra cash for a HPA tank, or want to save some money and get CO2. If you go CO2, make sure you get one that has Anti Siphon. Again, go to a local shop for comparison. I tried out different tanks to see how they feel on my marker (didn't bring my gun so I used the store's display to get a feel for the tank). I ended up getting a 68ci / 4500psi Carbon Fiber Wrapped HPA Tank since it felt more balanced on my gun than other tanks did. I use it as a shoulder stock as well, and that played a large role in size testing. I;m sure you could find a good deal for a used one here in BST, but still go to your local PB shop to check everything out. And remember to check the Hydro Date before you buy an HPA tank!
I'm more than happy to help, and so is everyone else. We'll do our best to help you make an educated decision.