Dry Sherry and Dry Vermouth are also good choices. They will keep for months after being opened, and they have a lot more flavor that other white wines. Gallo makes decent dry sherry, and I like Martini & Rossi Vermouth.
For red wines, consider the little 4-packs of 187ml bottles (about 1 coup each). The Australian brand Lindeman's or the California brand Sutter Home are good choices. None of these have much tannin or oak as they're cheap and made for early consumption.
BTW, someone suggested that it's the cheap California Chardonnay's that have too much oak. In my experience, the cheapies don't have all that much, and it's some of the more expensive brands that are over the top with oak. One good choice is Columbia Crest from Washington, about $5 for a 750 ml bottle -- very little oak, good fruit.