A decent rms meter will put right in the ball park in terms of getting multiple songs on an album to all sound the same level. 90% in the ballpark in fact.  A whole lot of fancy meters are actually not required at all.
 
Good ones are from Klanghelm and currently the Waves VU meter has a real nice ballistic, very close to the real thing.
 
It the cal level of the meter you need to adjust. For example on your final master buss you may want to target -12 dB FS as the rms level so you need to set the meter there and get all your tracks to just peak to 0 dB VU.
 
One thing you have to watch is that there are two types of tracks. Full on band tracks and acoustic tracks which may only have voice and guitar/piano etc or just very little instrumentation.  If you master both types of tracks to 0dBVU then the acoustic tracks will sound louder than the band tracks. Leave the band tracks alone and drop the quiet ones down -2 or -3 dB then they will all sound the same volume.
 
A VU meter with a nice ballistic will also tell you stuff too. A nicely mastered track moves the needle real nice right up to and just hitting 0 dB VU and not going over much. (If at all) If it is swinging wildly then you have not tamed the overall dynamic of the music too well. Go back and check your mix and also the mastering compressor.  ALL the best mastering engineers I have sat in with use the VU meter A LOT!!!
 
LUFS readings are on an average about 2 dB lower than rms levels (assuming the whole song is roughly at the same level all the way through) So a -12 rms master will be about -14 LUFS and a -14 rms master will be close to -16LUFS.
 
Some more mastering info here from me in this thread as well:
 
http://forum.cakewalk.com/Intro-to-Mastering-m3742240.aspx