Generally speaking, if you have a 3.0 GPA and 150 LSAT you can get into a TTT Law School. You may not be able to dictate where, but you can get into one. As I posted before, the admission process is highly ABA regulated. If you have either a GPA below a 2.5 or a LSAT score below 140, then the school needs a compelling reason why they admitted you. We have asked people to retake the LSATs if they possess a high GPA didn't hit the magic LSAT number.
These are the factors from an admission prospective:
Your undergraduate GPA is the biggest factor for predicting Law School success. It is the biggest factor in admissions. Some weight is given to your undergraduate institution. A person with a lower GPA from Harvard or (insert Ivy here) can get away with a poorer GPA. It is believed that the tenacity that it took to get into an Ivy will translate to business success after graduation. A person with a 2.0 Chemistry BS from State U can't get away with a poor GPA. I know Chem is a hard major. I know the argument: If you don't get into Law School, then you want some useful degree. Cope! Whatever you major in do well.
The LSAT is funny. It's a cash-cow for the ABA. Read into that. The big hint is that it is a test that can be studied for and drilled for(practice tests) to get a better score! What does the LSAT do? For the most part, the LSAT predicts 1L retention. If you have a very low LSAT; you generally don't seem to make it through your 1L year. The converse is true. After 1L, the predictive value breaks down rapidly. Seriously. After the test. You pretty much don't care who gets the corner office: Mr. White or Mr. Green. It's their problem. As a side note, after 1L year no one mentions or cares about the LSAT. I have never been asked on a job interview about my LSAT score. Nevertheless, the interviewer my extrapolate from the pedigree of my school its range. During interviews, I am mostly asked the same three questions: 1) What was you last big case? 2) How many clients can you bring with you? 3) how big/what type of Law did your prior firm practice?
You probably heard the line, "that a graduate degree will not get you into a professional program with a bad undergraduate record." That is not really true. An MS in Biochemistry has gotten people into Harvard Medical with a poor undergraduate record. Similarly, an MBA, MS, or MA has gotten people into a good Law School with a bad undergraduate GPA. Reread that last sentence. Grad School is a better course of action than staying in undergraduate realm and trying to boost you GPA with PE, Communications, Psych, or Art classes. Please note, some schools don't even factor in these add on courses.
If you are looking for your admission essay, personal recommendations, time in the Peace Corps, or whatever to get you in, then don't. The GPA and LSAT can move you the farthest. If a split decision comes between wait list and offer these factors can help. But, I wouldn't hold my breath.
That's my two cents based on my experience.