Well, Destiny's Child has had a lot of impact on today's urban music especially when it comes to the art of hiccuping over beats (No, No, No Pt.2, Bug A Boo, Independent Woman, etc ). You hear a lot of r&b singers riding beats these days. And a lot of people have been influenced by their rhythmic style.
I don't hear to much Spice Girls in music these days.
And by saying the Spice Girls are more bigger worldwide, you are insinuating that DC were locals which was not the case. Destiny's Child had a huge Worldwide fanbase, especially in Europe.
Oh, and if it wasn't clear my vote goes to Destiny's Child.
I say Destiny's Child is more iconic all the way. Let's keep it real the Spice Girls are only known for one song, and how many people who aren't fans of them can recognise and name all of the girls in the group. With Destiny's Child atleast Kelly, Michelle and others are somewhat recognised for being part of the group. Plus with Destiny's Child I firmly belive this generation can name songs off the top of their head from them. These songs include Say My Name, Bootylicious, Survivor, among other songs
Obvioulsy Avril will be rememeber and yeah I think Avril is more famous worldwide she only have 4 albums and she has sold waaaaaaaaaaay more albums
and no matter Rihanna have 1000000 #1 singles practically the mayority are very irrelevant Avril's #1 don't so yeah Avril is DEF more iconic than Rihanna.