Steam has easily the best gifting options of any gaming platform in the world, and now it just one-upped itself. Digital gift cards are purchasable starting today on Steam, which further elevates the options you have for gifting stuff to your friends. Surprising someone with a game can be hard, as all you really have to go on is their wishlist, and if they don't update it or use it at all, it just makes more sense to give them money.
Digital gift cards send funds directly to the receiver's Steam wallet, though the only downside is that you don't get to specify exactly how much (no $1.47 gifts, sorry). The cards come in the same tiers as the physical ones; so you can buy them in amounts of $5, $10, $25, $50, and $100.
Steam lists only two restrictions on buying the gift card. One, you have to be friends with the person you are gifting for at least three days prior, and two, you can't use your existing Steam wallet funds to buy a gift card. Other than that, buying them works almost the same way as it does a game, and better yet, you can let the person choose their own game.