I want to scope a Glock and need advice

[genesis49]

I have decided I want to get a new Glock and be able to shoot from as far away as possible, and accurately. At least 50 yds is what I'm going for right now, maybe more later.
I have decided to go with either the G20 or 21, probably the 20 though.
I have a Carver Hunter mount weaver rail, so I need an optic also.
Please help me decide which gun. I would like the reasoning behind your choice, please don't just tell me the number.
Also, what is a good optic to get. I don't want to spend a ton of money, but I will be saving up the $$$ for a little while, so up to $500 is what I'd be willing to spend.
This will be a long term project, so anything else you'd recommend would be appreciated.
I'm a little tired of buying multiple guns and not liking them as much as I thought I would. I want to concentrate on one project for a while.
Thanks for any help and recommendations you can give me

[green marauder]

I would say go with the G20 and get the Glock 6inch hunting barrel. There was a thread sometime back about shooting 100 yards plus with this setup. As for a scope I would go with a Bushnell Trophy Red-Dot, I had one on a 44mag I had and it held up real well. just my .02 cents

[Mountain10mm]

I'd opt for the G20 as well, and as the other person mentioned, get a longer barrel. You certainly don't need the longer barrel, but if you're shooting at 100yds, the extra velocity might be appreciated. The trajectory on a .45 is significantly more pronounced than with the 10mm.

As for the scope, hmm, can't say I've ever scoped a Glock, but I personally am not a big fan of the red-dot scopes unless you're using it for self defense or action shooting sports. I think the red dot covers up too much of the target (talking target shooting and hunting here) to be precise and accurate. I'd opt for a 2x or 3x Leupold or similar scope.

Show us pictures when you get the project going.