A good way to spark interest in your release is to include one or two recognizable covers. Whether your band's version is a carbon-copy or a whole new interpretation of the original doesn't matter. People like the familiar. They like Starbucks (I prefer Peet's); they like Barnes & Noble (I like Powell's); they like songs they've heard many times before.
But recording a cover song on your album says a lot about you or your band. Especially the decision on which tune to cover. Think about it: in the early days Led Zeppelin drew attention to their blues roots by including covers made famous by blues greats; the Rolling Stones did likewise and mixed in a fair amount of Motown originals to boot. Van Halen took off like a rocket with their debut thanks to their wailing cover of the Kinks' classic "You Really Got Me." The Talking Heads had early success with Al Green's soulful "Take Me to the River." The Cowboy Junkies hit the radar after covering Lou Reed's "Sweet Jane."
Each of these covers connected these relative unknowns to the original artists, for strategic reasons possibly as well as the fact that they're all such damn good songs. The upside is obvious, but it also means you better know what you're doing. If you're not giving the cover a new interesting treatment, you'll need to record a version at least somewhat on par with the original. But, in the case of my band Needle, it was well worth a shot. We covered Neil Young's "Helpless" and it's been our most popular song in terms of sales on iTunes.
Besides the artistic considerations, there are legal ones, too. You may wish to contact a lawyer for specific rights and liabilities (I'm not a lawyer and don't play one on TV, or even on this blog). However, I can say that in the case of our recording of "Helpless," we contacted Neil Young's publisher and received a compulsory license where we pay $0.091 every time we sell the song. A service I strongly recommend is HFA's Songfile, which is a web-based directory and database compiled by the Harry Fox Agency and can direct your request to record another artist's song to the appropriate publisher in most cases. It can also help identify the publisher if HFA doesn't handle the clearance.
To download Neil Young's "Helpless" as performed by Needle, Click Here