Funny you should ask. In this month's issue of All In magazine, there's a column by James Grosjean, author of Beyond Counting -- Exploiting Casino Games from Blackjack to Video Poker, on this very subject.
Grosjean concludes, "A matchplay coupon is a type of loss rebate. The best games are the ones that have high payoff odds, such as the 35-1 from hitting a single number on a roulette wheel. To extract the most value from the coupon, it's best to take a big swing, get paid in full when you win, but give up a worthless coupon when you lose (which is most of the time when betting a single number on the roulette wheel). Betting a color on roulette produces a value of $4.21 (for a $10 bet, so $42.10 for $100), while the longshot number yields $8.68—more than double the expected profit."
So longshots are best, but your matchplay has an even-money-bets-only stipulation. According to Grosjean, your best even-money bet is a blackjack game dealing specific favorable rules, including late surrender. Since this game will be hard to come by, the most practical bet with the highest return is the player bet in baccarat, which has an expected profit of $48 -- followed, in order, by craps, blackjack, and roulette.
For the entire list with associated expected values, see the January 2007 issue of All In magazine, which you can subscribe to by clicking here.
