Yes Bitcoin is the most gambled, and Ethereum is next.
I have a crapload of monero which I like as a coin, but it's a small % of the gambled coins. Would it be prudent to trade some monero for say litecoin or something?
What is the benefit of exchanging XMR to any other coin if your intention is to gamble out at the end?
Currently there is some sites that accepts XMR. Such as Crypto-Games.net & FortuneJack.com
Good Luck with your gambling.