Standard & Admin accounts

When I open "Local Users and Groups" and view the groups I see a list that
pretty much matches what is within XP. From what I have read there are only
two types of groups for Vista, Standard & Admin. I expected to see a
"Standard" group. I also read that the Power Users group, and I assume all
other groups outside of Standard & Admin, have been eliminated. Yet, the
Power Users groups is listed along with most others found in XP. If they
have been eliminated why are they listed? Why is there no Standard group
listed?

Thanks in advance,

JW