I feel like they need it more... they've just been hacked and they might need more resources to upgrade their security.
But both are good causes. But make sure you have enough emergency funds saved for yourself first.
Edit: Another argument for archive.org over wikipedia is that wikipedia is mostly a text based site. archive.org , in contrast, can store photos, videos, software, and various media thay requires more storage. The entire English wikipedia is only about 100GB (excluding videos), but archive.org is probably in the Terabytes or more.