We'll concede that the downtown library doesn't rank high on the aesthetics meter. If stateliness and charm is what you're after, you may want to curl up with a novel at the St. Paul Public Library's central branch. But in terms of sheer volume of volumes, this ugly 1961 edifice reigns supreme. We're talking 2,386,687 books and printed materials, 128,858 nonprint items (videos, CDs, CD-ROMs, etc.), and about 3,000 periodicals. In other words, the largest public library collection in Minnesota. The hours are a procrastinator's dream: The place is open till 9:00 p.m. Monday through Thursday and till 5:30 p.m. Friday and Saturday. During the past year, as the library has undertaken to revamp itself, some of the rough edges have been smoothed out. Most impressive: Those clunky green-screen catalog terminals were replaced in mid-February by new computers that also offer access to useful databases. And if negotiations go well, amenities like that may be trumped in the next few years by the construction of a new building.