Actually depends on the variables of your business, in my opinion. For instance, if your business is in a very large and competitive field, will it be easy or even possible to achieve organic results? If it possible, what time frame are you looking at in order to get ranked high, and what will it take to get you there, in real terms like time commitment, expenses, etc...? Can your business afford to sit stagnent with its online operations until you do start organicaly ranking? Will ranking high for the keywords you choose bring a suffecient amount of visitors to meet your online objectives and goals? How much money can you afford to put into a PPC program? Whats the competition like in your industry for keyword bidding?
My point is that there exsists a huge amount of variables involved with each individual web site in determining what online marketing plan is right for it. I would take the time to list all of your variables then try to work through the list to answer each one. After you do that you will have a much better idea on what options will work for you vs. which is better on a general scale.
One other point of note, SEM (Search Engine Marketing), is actually a broad term and encompasses other smaller designations of specific marketing applications like PPC and SEO, I only point this out because understanding the correct application of terms will increase your understanding of what you read about them, and will help you to make better informed decisions. It's OK to not know these things when your starting out, thats the whole point of learning and asking questions, so please don't take my correction as rude, I am just trying to help you understand the terminology for future reference. If your interested
here is an article that goes more in depth about that SEO, SEM, and PPC definitions.
Ppc vs sem
