Microphone Question...

If you specifically want a warmer tone but don't want to buy an expensive vintage mic, you might try an ElectroVoice RE-20.  I use it on my voice a lot and, since it is dynamic, you can also use it on guitar cabs and other sources if you like.  I recommend you borrow one before buying.
 
I am sure you know this, but opening the trim/input sensitivity too much or failing to pad the mic enough can result in a harsh tone.  This is a balancing act because I always want to get enough signal without getting the mic too hot.  Do you use the -10db switch on the SE X1?
 
Interesting comments here from Sound on Sound:
"...with the X1 sounding more airy at the high end — so it has clearly had a ‘bump’ engineered into the upper part of its frequency response. This will benefit singers whose voices lack definition, but it could also work against somebody with a naturally bright vocal character. SE haven’t carried the coloration too far, though, and with the gentle application of EQ it should be possible to achieve good results with a fairly wide range of voice types. (In my experience, there seems to be more leeway with male than female vocals, as the latter, for some reason, often seem to be much more microphone-critical.)"
 
 

The -10db switch was disabled, so I'll try enabling it.
The low cut was enabled, so I'll experiment with that.
 
The voice it sounds best with is... my own. But I'm recording less of that at the moment(!)
 
~ Tony

This thread is all about you question:
http://forum.cakewalk.com/Looking-to-upgrade-home-studio-vocal-mic-m2862625.aspx
 
It might be changing the input impedance of the preamp will make the whole full of joy. Also in the thread above.
 
Articles to review:
And:::::::: very important articles about how impedance matching/mis-matching affects frequency response.
Taming the Shure (57)
Shure SM57 Impedance Modification
A simple gizmo makes a big difference
http://www.recordingmag.com/resources/resourceDetail/330.html
 
When Mikey Met Ohmy
The effect loading has on the sound of microphones...
By Paul J. Stamler
http://www.recordingmag.com/resources/resourceDetail/266.html
 
 

 
There are loads of affordable pacific rim mics that are using copies of a German K67 capsule with a copies of circuits that were intended for a completely different capsule.
 
It's more common than not.
 
If you are using one of those mics... you are going to be haunted with a pesky upper mid range harshness.
 
 
best regards,
mike

I have an NT-1a which, while suiting my voice well, I would describe as a fairly bright mic.
 
A nice smooth, creamy vocal mic is an Audio Technica AT4047.  This mic has the ability to shave the rough edges off anything it is pointed at and has been my favourite mic purchase thus far.  It wasn't much more expensive than the NT-1a either.