I like eMusic as a source for downloading mp3s. I like to pay for digital downloads because I'm old-fashioned that way, but I don't like to pay extra at iTunes for a format that isn't used outside of the Apple biosphere. I often find the eMusic site clunky, but I suppose you get what you pay for. I do like it that they post charts and a year-end best of list. Here's a link to their top 100 albums of 2011. If you just go to the eMusic website without the help of this link, good luck trying to find it - I don't think you will.
One of the annoying things about eMusic is that if you just want to download a couple of tracks from a record you've never heard, it's hard to figure out which tracks might be the ones you'd want. You can read the reviews, but usually it's just a critic tossing out whichever tracks were the easiest for them to describe on first listen. If you take a peek at the record on iTunes, you can sort by popularity and then go back to eMusic to download the most popular or 3 most popular or whatever. It's a cumbersome and slightly time-consuming process, but it's less time consuming than weeding through it all on your iPod or computer after having downloaded to much garbage.
Then again, maybe you'd like that info, but you don't like the process. Here's the eMusic list with the iTunes top track (as of Jan15 2012).
The eMusic top 20 in descending order (with iTunes top track in parentheses) are:
20. We Are Augustines (Chapel Song)
19. Zola Jesus (Skin)
18. Tom Waits (Bad as Me)
17. Liturgy (Generation)
16. Drake (The Motto)
15. Fleet Foxes (Helplessness Blues)
14. Dum Dum Girls (Coming Down)
13. John Maus (Hey Moon)
12. Nicolas Jaar (Space is Only Noise if You Can See)
11. Youth Lagoon (Cannons)
10. Craig Taborn (The Broad Day King)
9. Cut Copy (Need You Now)
8. EMA (California)
7. Bon Iver (Holocene)
6. Beyonce (Love On Top)
5. Yuck (Get Away)
4. James Blake (The Wilhelm Scream)
3. The War on Drugs (Baby Missiles)
2. M83 (Midnight City)
1. P.J. Harvey (On Battleship Hill)
Don't be fooled by Beyonce at #6 or P.J. Harvey and Tom Waits at #1 and #18. This is mostly a great list for discovering new artists. Also, P.J. Harvey ended up at or near the top of a lot of year-end lists, so maybe I need to give P.J. Harvey a new fresh listen. Or maybe you just want to check out Yuck. It's up to you.