The weather may suck, but I can take strength from the fact that April is National Grilled-Cheese Sandwich Month.
I take great pride in my grilled cheeses, which I cook with a cast-iron pan, a sandwich iron and a drizzle of olive oil. The other big factor are ingredients -- I prefer sour dough bread and aged cheddar.
My ultimate GC comes from Borough Market in London: Poilane bread and Montgomery Cheddar. Not coincidentally, these are also the ingredients used by perhaps the world's best grilled (or, because it's England, "toasted") cheese makers -- Bill "The Raclette Man" Oglethorpe.
NY Magazine has a list of places to sample the grilled-cheesian arts.