I'm sorta in the biz myself, I do repair work for a local op and refurb machines to sell to the public (consignment at a local retail store). Here's some of my observations on the industry these days:
In the 80's arcades were a destination, in general now, they aren't. In my area, the only arcades that do much of anything are ones that are attatched to something else, such as a bowling ally or right in a mall. These days it's the "something else" that draws the people in, the games are secondary.
There are two arcades near me that do well, one is right IN the biggest mall, the other has additional attractions such as karts, mini-golf, batting cages etc.... All the others have closed down due to lack of biz.
There is also another one 150 mi from me that does killer, but they have indoor rides, one of those climbing/maze things for kids, food. The whole place is huge, that outfit has made it a destination and it's easy to take the kids there for a good part of a day.
The op I work for has his best locations are bowling alleys. He had a classic arcade for awhile, he rounded up all the classics he had and set them up at a small mall site. It didn't even pay the rent and he had to close it.
Classic games won't make you any money, but you have to have a couple. Maintence is high, they might cost you more then they make. People just don't pump quarters in them anymore. Sure, you get people like us to wonder in and play a couple of games for "old times sake", but we won't spend hours there dropping lots of quarters like we did in the 80's. Pins are the same way, you should have a couple, but they cost 2-3 grand new and they won't pay for themselves.
Redemption games are a must-have, period. So there's the hassles that goes with that, staffing, keeping prizes in inventory etc.....
You have to rotate games out on a semi-regular basis so they don't get stale... You have to consider that buying games isn't a one-time thing, but a steady thing. Auctions are one source, other ops. Outfits like Namco do sales every so often and sell the stuff they have rotated out. You'd have to keep on top of that.
It's really going to come down to your location. There are many arcades around the country that do very well as just arcades, other's can't make it without additional incentives to draw people in. Location/area seems to be the biggest factor and when starting out it's something you can never be sure about.
Try to offer as much as you can, do birthday parties/events, food (or get hooked up with a local pizza place to deliver/discount), Try to get as much varity as you can, vids, pins, air hockey, foozball... appeal to all ages so parents don't mind bringing the kids and hanging out with them. If you have the room, pool tables, indoor video driving range (and booze

) etc....
My point is, the more you have to offer, the better your chances will be.
I hope it works super for you, it's exciting to start a biz doing something you enjoy

Good luck!
D