As suggested on another thread, a discussion of the city's finest lime rickeys would be useful.
My vote: one of the two remaining Brighams left in the area, at 2 Trapelo Road in Belmont, does the best raspberry lime rickey I've ever had. It's not too sweet, and heavier on the lime than the raspberry, and -- crucially -- it's made with seltzer. This is actually a point of pride at this location. When the Brighams in JP closed, Allstonian and I overheard a couple of the teens behind the counter at the Belmont location talking about the closing. One of them said, "Well, I'm not surprised. They used SPRITE in the raspberry lime rickeys!" It was the tone of "how dare they?" outrage that got us -- would that more employees in ANY restaurant had that level of pride in their work!
I'm telling you, a Great American sandwich and a raspberry lime rickey at the Belmont Brighams is one of my favorite lunches in this entire city, summertime or any other time of year.