There is no reason to fear that pursuing a Dark Side path will curtail what you can do in game either. There are many possible benefits to going that route, including combat oriented items that are only usable by those who utilize the Dark Side. Force powers fall into three categories; Light Side, Dark Side and universal. Want to strangle somebody from a distance like Darth Vader? You can learn that Force skill (of course, it is a Dark Side power). A Light Side Jedi can actually learn and utilize Dark Side powers, but it will cost more skill points to obtain and more Force Points to utilize the skill.