Do you already keg? You're probably going to want to pick either pin lock or ball lock; nothing wrong with pin lock, but they're a little less common. So, you're basically committing to using pin-lock fittings going forward, you don't want to mix and match. In any case, three pin lock kegs, if good to go and pretty clean, are prolly worth $60 or so, from what I've seen (been doing a decent amount of research lately
).
Is it a dual or single reg? Duals, used, seem to be worth $30 - $50, singles, maye $15 - $30 used.
Carboys w/handles? $30 for pair I would think is fair.
Glass jugs - negligible. Those and the other gear, let's say $50 total.
So, excluding the monster CO2 tanks, I'd ballpark the value of the other stuff at $150 - $200, depending on how nice the reg is, how much other stuff there is, how nice it all is, etc. Might even be worth less to you, depending on how redundant some of that stuff is (the "extras" might be worth nothing to you, if it completely duplictates your existing gear).
So, would you then pay another $175 - $225 for two, 20-lb CO2 tanks? They're probably worth it, but are they worth it to you? Those are pretty big tanks - do you need two of them? Will you end up trading one of them for a couple of smaller tanks? Personally, two tanks that big would be redundant for me since I'm not going to have two kegerators, and they've got to weigh an arm and a leg.
I guess, if you really need those two big tanks, it's a fair price - but if those would just be "nice to have," you can probably find a better deal. For example, I got a 10-lb tank, three ball-lock kegs, a dual reg, and assorted fittings for $135+ shipping. Now, I'm pretty sure this was offered at a good price because this was from a fellow HBT'er, but I didn't think it was ridiculously cheap.
EDIT: Forgot that it was a nitro reg; that bumps the value, but to me, it still comes down to whether you really need two tanks that huge or not.