I alway debate between listening to a major label cd while mixing (to gain perspective) vs just trying to make the mix sound as good as it can for what it is. 

Dangers of Listening To A Major Label CD While Mixing

If you have ever mixed a recording for a "local" type band, you know that there $300 budget doesn't even cover the travel bill for most major label bands to travel to the big time studio of their choice.  I've found that I never play a major label cd with the band is around.  They'll immediately say "make my snare sound like that" or "make our guitars sound like that".  This mixing process does make a differenc, but you can not make your guitars sound other guitars by mixing.  You do that at tracking.  You can't 100% substitute a snare drum without the use of samples and midi because the overheard will still contain the shitty snare drum.

In my experience, mixes where I played mega recorded music has ended with the band pressuring me to focus on emulating that (which never comes even remotely close).  A great mix comes from taking the tracks you have now and manipulating those to get them to sound best.  Simply emulating never works.  This is why your favorite bands albums all sound quite quite a bit different. 

Advantages To Referencing A Major Label CD

I admit that I went through a time when I didn't reference major label cds because I couldn't figure out how to get that curve (no low mids...lots of highs) without drastically ruining my mix.

Well, now I listen to major label cds everytime I mix by myself.  I never try to emulate individual instruments, necessarily, but almost everyday I'll say, "Damn, those guitars are bright" on the major label cd.  Or in inverse, "Damn, my guitars are dull" on my mix. 

Play different major label bands songs.  Each one will sound drastically different, but all of them will probably have a similar curve.  This curve is what we all need to strive for to make our clients happy.  This curve has very little low mids most of the time and is often much thinner sounding than your original tracking sounded. 

Conclusion

Use major label cds to "influence" your mix, but don't waste your time emulating them.  It doesn't work that way when mixing.  It can help a lot though during tracking (where the magic really happens).  And NEVER NEVER NEVER let a band you are mixing hear the major label cd beside yours.  It can be a disaster.