As a fellow writer, I hope I can add a little to the thread. Ultimatly, the above post is correct, you get a more personal touch with ONE charecter in first person. In third person, you are more connected with everyone, and as such, you can avoid the small unimportant details such as picking up a pen for a later scene.
First person can be immersive and done well, but it is often jarring to read for the first chapters as usually everything else is done 3rd these days, so ease into it, and avoid jargon that the reader may not know yet.
Another useful technique for first person is to alternate POV's every few chapters. However, this can also be annoying. In one book I read that did this I ended up skipping the other POV simply because I wasnt interested in that charecter. So take it with a grain of salt.
A benefit of third person is it allows you to stream action sequences easier. For example, if helms deep was first person aragon, you would have to have him watching legolas during his airtime which is less dramatic than how 3rd person would address it. (also most movies are done in a 3rd person method as well, so if your hoping for a movie adaptation...)
There is nothing wrong with doing a 3rd person stance but focusing on 1 charecter like first person, only describing the ones feelings and what is happening around them.
There is also nothing wrong with doing it solely from one or more charecters POV.
The biggest factor is your own competancy. If you feel you write smoother from a first person or vice versa, do it. If push comes to shove, you can always adapt into another POV later, as long as you write the darn thing!
I hope some of this info helped even a small bit. I love reading other peoples work, so if you want to bounce anything off someone, I'd gladly do some reading for you
Oh, that reminds me, make sure you have someone willing to read your work regularly. You know how most books have that "special thanks" spot? Thats it right there. When you get someone involved, they reverse hype you into thinking deeper and get you excited about your own book. Watching them react is especially motivating. But if all they say is "sounds good." then you need to find a new reader. Find someone that gets as excited as you are writing the novel