I'm not talking about record sales. I'm talking about flow and all the things that make a rapper great. Tupac may have a lot of albums that went platnum, but that is mainly because he never left the record studio.
Wallace wasn't alive for that long, and he wasn't necessarily the sex icon that tupac was. That's it. Tupac had a longer rapping life than BIG, not to mention he was and is, considered a sex icon on the level of what LL Cool J is now.
Although this is not the place to have this debate, when it comes down to flow, rapping, and just plain old telling a story, Biggie takes it. Tupac's rap consists of drinking, sex, and drug use (With the exceptions of a few songs), Wallace could rap about anything.