The Sky Blue Sky's hardly the limit for Wilco these days.

Unlike bands whose live set begins and ends with their latest album and greatest hits, the veteran alt-roots sextet find themselves in a more flexible and impressive position on their latest tour: They stand ready, willing and able to play virtually any of the 100-plus songs in their catalog.

It's the happy result of a multi-night residency the band recently undertook in their home town of Chicago, bassist John Stirratt explains.

"Over five nights, we played every song we ever recorded," says Stirratt from his new home in the Windy City.

"It really breathed new life into things. We played a lot of songs that we might have only played once or twice before. This lineup of the band got to make every era of Wilco its own in certain ways. And it's helped the live thing continue to grow and be enjoyable."

The band is even taking requests -- but if you want to hear Bob Dylan's 49th Beard, don't scream it out between songs; go online and fill out a form at their wilcoworld.net website.

"It's been great," the 40-year-old Stirratt says of the interactive policy. "There have been a few instances of Stump the Band here and there with B-sides and covers, but nine out of 10 times, we can actually do the song somebody is requesting. And I like doing the obscure tunes. Knowing how capably these guys can play them makes it fun."

For the record, "these guys" are drummer Glenn Kotche, keyboardists Pat Sansone and Mikael Jorgensen, guitar hero Nels Cline and, of course, singer-songwriter and frontman Jeff Tweedy.

Stirratt is eminently qualified to judge the merits of Wilco's latest lineup. After all, aside from Tweedy, he's the sole survivor of the original band that rose from the ashes of alt-country pioneers Uncle Tupelo in 1993.

But it's not as if his years of dedicated service have earned Stirratt any special treatment.

"What does seniority get me in Wilco?" he muses. "Well, let's see. I have a bunk on the bus that I pretty much have reserved. That's pretty much the extent of that. But then, I don't really expect anything more. I don't really carry more weight than anybody else."

While Tweedy continues to be the band's primary songwriter, Stirratt says that egalitarian approach extends into the rehearsal hall and the recording studio -- two places the band will be spending a lot of time soon as they gear up for their seventh studio album, the followup to last year's Sky Blue Sky.

"We're in the beginning stages right now," he says. "We're writing for it. We haven't really gotten together and recorded anything yet, but songs and ideas are switching hands."

Based on what he's heard so far, he suspects the album could be "louder or more rocking" than the mellower and more melodic Sky.

"Then again, I always have an idea of what we're gonna do, but it doesn't always hold true. We leave plenty of room for creation and augmentation in the studio. The last record was a really good example of that. So who knows how this one will turn out in the end?"

Or what genre it will be arbitrarily assigned come award season. After being nominated for a Grammy in the folk category in '90s for their Mermaid Avenue tribute to Woody Guthrie -- and later winning Alternative Album of the Year for 2005's A Ghost is Born -- Wilco found themselves vying for Rock Album at this year's soiree, going up against Daughtry, John Fogerty, Bruce Springsteen and Foo Fighters.

"That was pretty funny," laughs Stirratt. "It's like we were placed in that category solely on the basis of our guitar tone. But I guess it says to me that there's a good amount of versatility in the band."

See for yourself when the band returns to Burton Cummings Theatre tomorrow to make up for a show they cancelled last year after Cline came down with chicken pox. Tickets are $29.50 to $42.50 at Ticketmaster.