Issyg67 - I've had seats up on the Monster twice now (once last year and once this year) and once up on the new RF Roof Seats. The RF seats are awesome...there's a bar up there and tables shaped like home plate. Its a great experience, but if you have to go one way or the other...how can you pass up sitting on the Green Monster? That Wall is legendary. I've been to hundreds of sox games and have sat everywhere imaginable in that park and I cannot think of a better place to watch a game. The view is amazing, both of the city and of the ballpark. Its not like sitting in the bleachers where you feel like you are far away....you are right on top of the action. Even if you can only get standing room tickets up there....the experience is not lost...there's plenty of room.
Getting tickets is a different story. Its the hardest ticket to get in boston. AceTickets is one of the few places you can get them. Alot of the scalpers outside of Fenway work for AceTickets but they rarely sell the Monster seats outside the park.
Your best option may be to buy a cheap seat....walk up to the kid at stairs of the Monster and give him $10-20 bucks for every person you are with. Don't ask him how much, dont let him hesitate to say something...just give him the cash and keep going.
Also, if you are visiting in July there's a couple things you should know. The DNC is here and the entire city is getting shut down the week of July 26th-30th. Its going to be tough to get around during that time frame do to security reasons. The Yankees are here on the 23rd for the weekend as well.