First off, the claim that this energy is limited seems like a great way for people to justify all kinds of urges they would normally restrain in an effort to 'conserve' this energy. This could be a major pitfall for people trying to attain personal growth.
Looking at it from the opposite side, we realize that if we are trying to grow as people, it is beneficial to grow gradually and constantly. Normally, people try to make major life-changes in a single day. From today I will start this diet. Today I will quit smoking. I won't gossip anymore. All of these attempts, they will all meet with failure because either: 1) working on this sudden change will interfere with all the other aspects of your life, or 2) the other aspects of your life will interefere with this goal and override it very quickly.
Instead of radical changes, gradual changes are much easier and more powerful to incorporate into one's life. Making a small change and sticking with it for a month will have positive results both because you will have kept to it, and because you will have the positive feedback of the feeling of having accomplished something. String together a whole year of months like this and pretty soon you will be eating healthier, smoking less, etc.
The real point though, that I think is essential for a healthy Jewish lifestyle, is to incorporate chumroth (stringencies) very slowly. Rebbe Nachman of Breslov would let a new behavioral change or new minhag roll around in his mind for months before taking it upon himself. (Similarly the mystics of Tzfat (Safed) would ponder their students' questions for weeks before supplying answers, lest they err in answering too quickly.) It's vital that we improve our mitzwah observance, but it's just as vital that this mitzwah observance be a lasting improvement on our lives.
Perhaps through this period of counting the Omer each of us will be able to climb gradually toward receiving the Torah this year. And I bless us all that the Torah that we attain during this sefirah will stay with us throughout the year to come, and throughout our lives.