I would rather see a small refund (<$100) than owe anything. I've never owed before, and I'm not sure how much of a hassle it is. (Do you enter a credit card number into your tax return? Do you have to mail a check? I'm terrible with mailing things- I'll put it off for months.) This year is the first that DH and I are filing married, and I had a month unemployed while he got stationed to a foreign country, and then I got a promotion and he got a pay raise (all at different times of the year), so I wasn't sure what to expect. This year, our refund was almost $2,000, which is WAY too much. However, through H&R Block, we were able to receive our refund in $100 increments on an Amazon gift card and they added a 10% bonus on that amount. So we received a 10% ROI (9.7% ROI if you calculate based on the full refund amount) at the end of the "interest free loan to the IRS." We will use the Amazon gc throughout the year to purchase US goods that we can't acquire locally, which will lower our grocery bills for months to come. Yes, the extra $2K would earn gains and compound over years, but we could do worse than a one-time 10% ROI too... like use our refund as a "down payment" on some shiny thing at Wal-Mart...
Also, we have both adjusted our withholdings so that a $2K refund doesn't happen again- 10% bonus or no. ;-)