I'm debating on whether to buy the macbook pro 13" 2.53gHz over the 2.26gHz which costs about 150 less before tax (I'd be upgrading the stats on the lower one).

Is the .27 gHz more worth the extra money?

In my opion I would spend the $ on RAM it is only about a 10% boot in processor speed, adding RAM should give you more noticeable improvement.

I agree. Always buy a computer with the slightly slower clock speed, and with less RAM. Then spend the extra for more RAM, and install it yourself. You also want a good dual-core or better processor, and a video card with dedicated RAM. Those are expensive to upgrade, and can have a big impact on performance.