I'm usually a lurker, but thought that I had to post on this one as someone who worked for a tobacco company a few years ago.
I'm very much anti-smoking, never smoked, never will, find it absolutely vile. For all the reasons already mentioned by other posters, I hesitated when I saw the job advertisement even though the job description and other factors were perfect for me.
BUT, if you think it through, there are.lots of industries that are similarly 'bad' as tobacco companies (e.g. food companies that try to sell very unhealthy food by heavy marketing, often targeting children, implying nutritional value were there is none or even the opposite, thereby disregarding evidence of negative health effects of certain foods). So, if you think it through, you'd have to avoid a wide range of industries.
The other thing is, the pay at tobacco companies tends to be very good. I don't know about your specific offer, OP, but I'd have imagined that you would have got a good offer which is why you consider taking it despite your reservations?
And then again, I think it depends on what kind of role we are talking about. If you were going to work in marketing, acively promoting those products, I too wouldn't want to do it. But if you're talking about work in a department that isn't that heavily involved in the product content and marketing (e.g. distribution, accounting, legal) then I don't see an ethical dilemma in your work content. It would be pretty much the same as working for any other kind of company.
I wouldn't worry about the effect on your cv that was mentioned by another poster, since it is, after all, just a job. If it makes sense career wise, I don't think that any recruiter later on will view it negatively. Curious about your motivation/thinking they might be, but it shouldn't affect your future job perspectives negatively.