#1
I took a trip to a local store called Quest Musique and had a look at their cabinets. Here's a list of a lot of the stuff they had in the store:

http://www.questmusicstore.com/c-91-guitar-speaker-cabs.aspx

First off, the prices blew me away. I really don't know a lot about guitar cabinets, but marshall cabs for under $500 and Bugera/Behringer cabs for under $250 seemed like a steal to me. Has anyone used some of the cabs listed here? I've looked some of them up, like the Bugera 412HBK and it seems to get pretty good reviews. How would these cabs compare to some of the usual cabs recommended around here?

Secondly, what difference would the wattage make? I understand that higher wattage amps need to go louder until they hit that perfect sweet spot, and that having an amp wattage higher than your cab wattage is a big no-no (unless staying at low volumes and you're careful). But what would be the difference in using a 60w head through a 120w, 200w, or even 240w cab? Would it actually be louder, or just give more headroom and sound clearer? If you had a 60w head, would it still be worth it to get a 200w cabinet?

And lastly, what about the number of speakers? From what I understand, more speakers doesn't necessarily mean it'll be louder because the signal is being split upon the 2/4 speakers. So more speakers also gives a better bass response, a fuller sound, etc. Would it also give more headroom, since it's 2 or 4 speakers doing the work than one or two?
#2
those seem like the right prices.
bugera cabs are made in china and come with oem bugera speakers. for 500 you're probably looking at the marshal avt cab which is made in china and comes with probably the worst speakers ever made.
Prs se Holcomb is the answer
#3
Heya bro, you must be from Winnipeg. Same here.

Got my Engl at Quest and I'm friends with all of the guys who work there.

You shouldn't worry too much about wattage. Just decide whether you want a 4x12 or a 2x12 and go from there. FWIW that Orange cabs at Quest are hands down the best ones there.
#4
You want the wattage to be at least 50% more than the rated output of the amp, just to be sure it wont damage the speaker even if you crank the amp You should get more headroom from speaker distortion, but not poweramp distortion. It also wont give you more volume, speakers are rated for power handling, not output.