Hmmm I was thinking of actually changing the monkey on the back and making him look more like the one on the face, something just seems... off about the monkey on the back. I like the simplicity of the face card but again depends on everyone elses opinions.
An idea, that ive tossed around a few times, what If I took the ape heads off? It would make the whole deck look alike because of simplicity I think.
A few thoughts:
If you remove the monkeys, this deck loses everything that made it distinctive - it would be little different than any other deck used for poker, and thus just as interesting or exciting as a pack of standard Bikes. Even exceptional paper and finish might not be enough - people can't see paper or finish on a computer monitor, but they can see your designs.
Get rid of the outside frame on the faces. It serves no purpose and hinders more than it helps.
Your indices are way too small. If you're going for standard indices only and you want to see your deck in the US, lose the right-corner indices. They would only appeal to the ~5% of the population that's left-handed.
The flat gorilla art on the faces looks better than the 3D art on the back - stick with the 2D appearance.
I've never before seen a pin-striped fedora that matches one's suit! If you want a "roaring '20s/speakeasy/gangster" look to your face cards, stick to the standards of that era - fedoras were generally brown, grey, black or (if you wanted to look flashy) white. Perhaps you could get away with a dark green or a navy, but justify the reason - have the character wearing the same color suit, or shirt at the least. They'd all have wide hatbands either the same color as the hat or darker - brown and black were the most common. Some would fancy it up a bit and have a small feather or two stuck in the band's bow.
You know my preference regarding the appearance of the card backs. But if you're aiming seriously at the poker crowd, a solid color is good. Just consider something other than black - it makes your artwork look like it's being sucked into a black hole.
While I know you're planning to make two different colors on the back borders, you may want to alter the shade more than just the colors - poker decks are generally distinctively different colors from each other, the most common ones being red, blue, brown or green. The reason for this is to reduce the chances of a card from one deck accidentally ending up in the other. Different border colors, in my opinion, aren't enough by themselves. An example of bad design along these lines would be the COPAG EPOC deck (all black backs, marginally different red and white patterns between them -
http://www.pokerchiplounge.com/playing-cards/100-plastic-playing-cards/copag-playing-cards/bridge-size-copag/bridge-size-copag-jumbo-index/copag-bridge-size-jumbo-index-EPOC-black-set-up.html) and the KEM WPT deck (colored in black and grey, making them hard to tell apart from each other -
http://ep.yimg.com/ca/I/yhst-11171180798419_2197_62454253).