In her new column at Chess Café, Abby Marshall sums up nicely the reasons for playing the Tarrasch Defence:
It’s a great opening for improving players, because it’s very important to learn how to play open positions with active piece play; while not any position can become closed, any position can become open. The Tarrasch can also be played against almost all queen-pawn openings. And, it’s fun.
This is exactly why I am currently building my opening repertoire around isolated pawns and opt for openings such as the Tarrasch. Prodigal Pawn has kindly agreed to share some annotated games on the subject of the isolated pawn, and has a freshly annotated game by Anderssen against Morphy up at his blog.
Meanwhile, Michael Goeller harkens to the Smith-Morra’s siren call. I’ve been playing the Smith-Morra myself against the Sicilian because I was concentrating on open lines and thought the Smith-Morra offered plenty of opportunities to practise attacking play. I’ve even scored a (dubious) victory against a 1750-player in a 90/20 game. However, I’ve got this hunch that the Smith-Morra doesn’t tend to follow “natural” attacking patterns, so I might drop it in favour of the Alapin variation — sticking to the c3-push but with a more solid long-term plan. In case you’re interested in the Smith-Morra, Michael links to a “super Smith-Morra webliography”. Good stuff.