I do stock work for a living, so I strip a lot of stocks, probably 3-4 each month. The best stripper I have found is Citristrip, available at Home Depot, Lowe's, WalMart, etc. It will even lift off the tough clear finishes like Browning or Weatherby use. Put on a thick coat of the goo and let it sit a day or so, then wipe or scrape the finish off and wash the wood with cold water after you are satisfied with the stripping job. Sometimes I need a second coat, but it is usually a one-step stripping process.
As far as the best finish available from hardware stores, spray polyurethane works well, just use thin coats, and sand between coats with 400 grit or finer paper.