http://www.russell.com/documents/indexes/us-index-comparison.pdf
russell 3000 = 1000 more stocks than russell 2000
I know you were just messing around, and maybe doing a little deserved
LMGTFY, but since it's not obvious that you actually understand the difference, and surely many other people don't (since it's not intuitive), it's worth being explicit about it again as seattlecyclone was.
If I told you:
- Russell 1000 is the 1000 largest US companies
- Russell 3000 is the 3000 largest US companies
and asked "What then is the Russell 2000?"
I bet 80% of 5- to 85-year-olds would say
"it's the 2000 largest US companies".
Because that's a lot more intuitive than the real answer, which is that
it's Companies 1001-3000.
So again, "go with the lower ER" isn't really a good answer for someone looking for an alternative to an S&P 500 fund, because the Russell 2000 is essentially
the opposite of an S&P 500 fund, explicitly avoiding the large-cap companies in the S&P 500 index.
In this case, yes, the Russell 3000 is probably your best alternative to an S&P 500 fund (from my understanding a big reason S&P 500 funds are more popular than total-market funds is just because they were around first, not because they're "better").