As you consider whether or not to get a flu shot for either the regular seasonal flu or for H1N1, you might want to read this analysis of the evidence for seasonal flu vaccination from the BMJ:
In children under 2 years inactivated vaccines had the same field efficacy as placebo, and in healthy people under 65 vaccination did not affect hospital stay, time off work, or death from influenza and its complications. Reviews found no evidence of an effect in patients with asthma or cystic fibrosis, but inactivated vaccines reduced the incidence of exacerbations after three to four weeks by 39% in those with chronic obstructive pulmonary disease. All reviewers reported small data sets (such as 180 people with chronic obstructive pulmonary disease), which may explain the lack of demonstrable effect.
The same author in a different article makes the interesting point that only about 7% of what seems, casually, to be flu -- "ILI", or influenza-like illness -- is actually influenza. Obviously an influenza vaccination is not protective against other, more common causes of ILI.
I've never gotten a seasonal flu shot, and given this lack of evidence for benefit in the general population, I don't plan to start.
As for the H1N1 "swine flu" that's causing such a panic, it should be noted that it severity is comparable to the regular flu: this is not some superbug. According to the WHO, "national levels of severe illness from influenza A(H1N1) appear similar to levels seen during local seasonal influenza periods, although high levels of disease have occurred in some local areas and institutions."
Meanwhile, the evidence on the safety and efficacy of the H1N1 vaccine simply isn't in yet.
If I belonged to a high risk group, or was at high risk of exposure, I might consider the FluMist version of the H1N1 vaccine. (The FluMist version is a live virus vaccine, and so is not suitable for everyone, but it does not contain thimerosal. I think putting any easily-avoidable organomercury compound into your body is a bad health strategy.)
But as things now stand, given the low risk that H1N1 presents to healthy adults, and the non-zero risk of complications from vaccination, I will skip it.