If you are in South Arlington or the Center, La Bella Foods in West Medford is a bit closer than Bob's (and D'Agostino's) but is a similar Italian deli with prepared foods. (Bob's or even a bit further Maria's Cold Cuts in Somerville are a bit better and more complete.)
For a less expensive option, La Ronga on Somerville ave near Porter Square does platters. I slightly prefer McKinnon's selection, but I don't think they do platters. Sessa's nearby has more interesting salumi. Dave's fresh pasta could also do something interesting.
Depending on where in Arlington you are, I'd recommend either Neillio's in Lexington or Bob's in Medford. Neillio's roasts their own turkey breast and roast beef daily and has all kinds of home made entrees and sides. Bob's is a more old school Italian deli with everything from prosciutto and sopresatta to steak tips and sausages.
Bob's Imported Food & Catering
324 Main St, Medford, MA 02155
Neillios Gourmet Farm
53 Bedford St, Lexington, MA