An interesting question for all coins is -

How much does it cost to maintain the coin at its current price level?

It gives you an idea of how much money is currently flowing into the coin, and resources being used to secure a coin's network. It's easy to work out - you take the current price and multiply it by the number of new coins created each day. I've compiled a list and it currently has some interesting coins at the top, and some interesting coins at the bottom - here it is

Top Coins
Bitcoin -     800x25x6x24 =           2.880M
DogeCoin -    0.0018x500000x60x24 =   1.296M
Litecoin -    20.57x50x24x24 =        0.592M
Mooncoin -    0.00019x1000000x40x24 = 182,400
Peercoin -    4.53x114.44x6x24 =       74,651
ProtoShares - 10.20x16.177x12x24 =     47,521
WorldCoin -   0.29x53x120x24 =        45,792
Primecoin -   2.65x10x60x24 =          38,160
Namecoin -    4.88x50x6x24 =           35,136
Feathercoin - 0.27x200x24x24 =         31,104
Novacoin -    12.72x9.3x6x24 =         17,034
MemoryCoin -  0.20x216x10x24 =         10,368
Megacoin - 0.57 - 25x24x24 =              8,200
DigitalCoin - 0.2510x15x90x24 =         8,100
Devcoin  - 0.00059 - 50000x6x24 =   4240

Bottom 3 'Big' Coins
IFC      - 8.3e-05 - 4096x120x24 = 979
Quark    - 0.074 - 4x120x24 =      852
Zetacoin - 0.02 = 4x120x24 =       230

*Let me know if I've missed any - just looked at the top20 and the ones i'm interested in.