I've used several brands of Vitamin C over the years, but recently I've been using Nature's Bounty. For the price (about 4½¢ per tablet) and quality, the 500 mg tablets are a good value. I take 2 tablets a day (1,000 mg/day). My doctor doesn't specifically recommend any vitamin supplements, but she has no problem with me taking a moderate daily dose of Vitamin C.
As round tablets go, these aren't too big (about 11 mm in diameter), so they should be easy to swallow for most people.