Lullaby is a S&S spell that makes targets in an area "drowsy," giving them -2 Spot/Listen and saves vs. Sleep.
It was made 1st level in S&S, though cantrip is probably more in line with its power. The spell description requires you to actually play a melody, so I had a very difficult time envisioning ways to use it that would be worth a 1st level spell slot (obviously, a -2 on Listen has limited application when the target is already listening to you). The book says it's good to use when you're trying to fool someone with a ruse that requires Spot or Listen checks, which I guess I can see, but it's not a common enough circumstance or big enough effect to merit 1st level status, especially when Fascinate covers a lot of its ground anyway.
With Virtuoso, I can't imagine how it could be considered a power-enhancing option even for bards, much less for wizards. Sustaining Song's effect is subsumed by Inspire Greatness in all but the most unlikely circumstances (like several allies in negative hitpoints in a zone of silence), so you've got to forgo two levels of medium BAB, good Ref save, over half of your class skills, and Bardic Knowledge before you get anything at all out of it. The later songs are mostly OK with one or two standouts at high level, but if you wanted to spend 10 levels getting wizard/sorcerer BAB and saves to get one odd spell effect per level (after 2nd), it seems like you might as well have just taken 10 levels of wizard or sorcerer (or druid or cleric or some other main-line spellcasting class) and gotten a whole bunch more spell effects faster. Virtuoso does have a thematic place as the PrC for the bard who really specializes in the magic side of the class, but nerfing Virtuoso is like nerfing a whiffle bat.
(The usual at-first-glance argument about how Virt is so great for sorcerers etc. falls apart when you consider the stiff skill rank prereqs - it's a viable, if somewhat mechanic-straining, option for a sorcerer, but it's not the key to the power bank - it will certainly cost two levels of skill stuffing as bard or rogue and even that takes a DM who can swallow massive single-level skill increases.)
Personally, I think the idea of having "song" spell effects and spells-that-you-have-to-cast-vocally in 3E was a little wrongheaded anyway, and adding a bunch of slightly altered spells to the "song" list just makes it seem even more like the 3x bard/virtuoso is using two different mechanics to get the same effects.
In 2E, bards had a distinctive "song" magic in the form of songs and they also could act as amateur wizards by casting spells in the regular arcane fashion, completely apart from their "song" magic. It could certainly be argued that bards shouldn't have been junior wizards (though I would disagree), but the point of having both song-like spells and spell-like songs escapes me, other than of course the backward compatibility issue.