I'm going for a restocking-run, and I'm looking to pick up some beers I haven't tried yet. In the eyes of the BA community, what readily available shelf beers would be considered essential to try? I've gone pretty thoroughly through the offerings of Stone, Unibroue, Ommegang, Lagunitas, Rochefort, Dogfish, St Bernardus, and I'm looking to branch out. For reference: I'll be going to Half Time in Mamaroneck, NY, which has a pretty awesome selection. Thanks all!
Oskar Blues and Captain Lawrence; just off the top of my head. Abbaye des Rocs for solid Belgian strongs.
Look at the Beers of Fame list. I find a good amount of these beers are available. http://www.beeradvocate.com/lists/fame/
If they have Jack's Abby there, get some. It's available in some NY locations, but not all. It will be worth your while to check it out.
Locally, besides Sixpoint and Captain Larry which have been mentioned, I'd say Great South Bay, Coney Island, and Two Roads (EDIT: I think Two Roads is from CT actually) to try them all, especially GSB. I really like what they've been putting out. Coney Island's Seas the Day is an awesome IPL too. Outside of NY, there's always Westbrook and Cigar City shelf beers if they have them. Maybe Clown Shoes.
Recently at half time I was able to grab some Wulver and BA Siberian night, variety of jacks Abby, and that central waters chile stout. There is rarely a lack of good things to buy there. Also you may want to check out what they have on for growlers. Get some rushing duck war elephant if you see it!
Also don't sleep on the various deciccos stores in westchester, I usually find something great and unusual whenever I visit.
I looked at your reviews. Seems like you enjoy Belgian beers. If you haven't tried Orval yet, consider it a must. If you are looking to branch out, try an English barleywine (either Adnams Tally Ho or something from a US brewer and of the non-bourbon variety), or try a German doppelbock like Celebrator or Korbinian. I would second the Bell's recommendation for a US brewery to explore. I'm a fan of Pretty Things and I'd see what they have in stock that's relatively fresh from them. I don't know Half Time's growler policies, but if they give samples and fill 32ozs, I'd dive into that for local-ish options. As mentioned above, War Elephant is fantastic. From the tap list on beermenus, I'd ask to sample the Carton 007XX and the Barrier porter.