After several WordPress updates and some lost Analytics data, I have come to a conclusion: Get a plugin for Google Analytics to use with WordPress. Before realizing that there was a simple plugin, I was placing the Analytics code on my site manually. On at least two occasions, I upgraded WordPress and forgot to reinsert the code losing a week or so of Analytics data each time. Now this isn’t vital for me, but the simplicity of the plugin is great.
I use Analytics with WordPress. Some may prefer another option, but I haven’t had any trouble with this one through a few upgrades, so I feel comfortable recommending it.