Its personal preference mostly. But for presentation purposes, its definately gloss.
Prints never last very long (shorter if you expose them to strong light). The only way to preserve yr picts are to store the negatives into a dark cool dry place. A dry cabinet works pretty well.
Matt dosent stick to the frame or attract fingerprints as much as glossy does. I prefer to print as matte for this reason. I dont store prints as archives but as mentioed earlier I keep the neaatives in a cool dry place