Once upon a time, the building at 15 Dunster St. was a bank. Today, people drink milkshakes in what was once the vault, and teenaged scoop jockeys dole out mint chocolate chip where tellers once doled out cash.

On many summer evenings, in fact, the atmosphere at Herrell's will remind you of a scene from one of those Depression-era movies where the whole town makes a run on the bank. Just half a block from the Harvard Square T stop, it's no wonder that this popular parlor often plies its wares to standing-room-only crowds.

But it isn't just Herrell's location that makes it a favorite for many connoisseurs of Cambridge 'cream--or the winner of The Crimson's coveted trophy for ice cream for the second consecutive year. The flavors here are rich and smooth, with a homemade taste that comes from the ice cream being made directly on the premises.

The ice cream here is so rich, in fact, that you're best off combining flavors so as not to suffer an overdose of one or the other. The chocolate pudding ice cream, for instance, shouldn't be taken straight except by serious chocoholics. Try complementing it with something a bit lighter, like malted vanilla or espresso.

Or you can always ask for one of Herrell's popular "smoosh-ins"--regular flavors mixed with dry toppings like Oreo bits or M & M's. They're called smoosh-ins because the employees actually knead the toppings into the ice cream.

Herrell's is owned by Steve Herrell. Herrell founded the original Steve's, but sold out a few years ago. When he decided to get back into the ice cream business, he found that he had also sold the right to use his first name in the name of his new store.

Without Herrell's management, the once-proud Steve's has sunk to the bottom of the barrel. It is the one ice-cream joint in the Square where you likely won't end up. The biggest problem with this pathetic parlor is that they don't even make ice cream look appetizing. That's pretty bad.

If you do end up there, don't go for the mix-ins, because watching Steve's inexperienced workers mush gooey Snickers bars into your vanilla ice cream against the counter will make you sick to your stomach. At Herrell's, watching them make smoosh-ins is like watching artists at work. At Steve's, it's like watching little kids play with their food.

Another problem is that Steve's has expanded into a sub and sandwich shop as well. Our advice to them is that they should just stick to the real thing, and try to perfect that first. Our advice to you is that you should go somewhere else.

Herrell's nearest competitor for the Cambridge ice cream crown, is Toscanini's Ice Cream, a short walk down Mass Ave toward Central Square. Were Toscanini's a bit closer, it could claim the Bogart Trophy for itself.

A perennial favorite among students and residents alike, Toscanini's makes its own ice cream, too: Cocoa Pudding and White Chocolate are two particularly tasty delights. And Toscanini's is relatively affordable, at least compared to some of its competitors in the Square.

So all in all, the trip to Toscanini's is definitely worth it.

For gourmet ice cream, Emack and Bolio's creations are pricey, but well worth the money spent. If you're on a diet, though, pass. Emack's is very rich.

Try some of the fruit-based ice creams. Apricot is terrific. Chocolate lovers, too, will be pleased at the variety of ways they have to satisfy their addiction. It's tough to go wrong here, except that the frappes are extremely thick, and practically guarantee atherosclerosis.

Baskin Robbins probably needs less introduction than its fancier counterparts. As it proudly boasts, it has more than 2600 outlets nationwide. Still, simplicity has its own charm. Sometimes a burger at a greasy diner satisfies the palate more aptly than does nouvelle cuisine at a black tie eaterie.

This does not imply that Baskin Robbins's utility is limited. Some of its 31 flavors, such as strawberry banana or peanut butter and jelly, may be hard to come by elsewhere. Still, the old-timer generally does its best at the old time flavors, so try the mint chocolate chip or the chocolate (many variations) if you're exploring this relic.

If you're looking for something a little lighter than ice cream's caloric richness, try one of the Square's many frozen yogurt shops. In the last few years, three stores exclusively devoted to fro-yo have sprung up in the square, and many of the ice cream shops also offer "gourmet" frozen yogurt.

The square's most popular frozen yogurt shop is Lucious Licks on Eliot Street. Licks' menu offerings change daily, but you can usually count on a good combination of standard and funky flavors. Licks has developed something of a cult following among Harvard students, but critics often complain that its yogurt is too heavy and bloating.

Around the block is Temptations, which opened last year on the site of the old Haagen-Dazs. Temptations has more offbeat flavors than Licks does, but its mall decor is slightly unsettling. Temptations also weighs your yogurt portion, lest they give you that extra tenth of an ounce. Personally, we feel violated when someone weighs our yogurt.

TCBY (The Country's Best Yogurt) in the Garage is the Square's newest frozen yogurt store. Although the shop is only one outlet in the TCBY empire, its convenient location and lower prices are fast making it a favorite among local yogurt seekers. TCBY's flavor selection is often uninspiring, but its yogurt is lighter than Licks' or Temptations,' and students often find themselves forgoing the latter's gourmet flavors for TCBY's simplicity.

So enjoy the Square. Wander around, but don't forget to bring napkins, because whatever you get, it probably will drip.