There are several options, but you need to decide what you really want. In addition, what environment are you running in now? Windows xp has plenty of copying solutions, windows 7 has fewer and less robust solutions, and Linux has its own built-in commands.
1) Clone one hard drive image, then roll it out on several computers. This method requires volume licensing (which your business might have), and will be the fastest deployment. Conversely, it also requires the most rigid image (everyone gets everything basic, then has to install their own specific stuff).
2) Everyone gets their current HDD cloned to a new SSD. This will be a time sink for your IT. It also has the potential to be problematic if you are using older hardware that doesn't support write levelling algorithms.
3) Fresh installs all the way around. This would be the most time consuming solution. On the other hand, it would allow for the fastest computer speeds (fresh installs always do) and force people to clean up their information. A little bit of cleaning, with the old HDDs kept for a few months to prevent data losses, might be a smart decision.
If you're going for 1, the best solution is probably Norton Ghost. They do large roll-out very well, and it won't take IT the better part of a week to do the company if there are more than a dozen computers.
If you're going for 2 there's quite a few more options. Paragon, as stated by others, is a good cheap option. There are other free options, though their compatability with windows 7 is sketchy at best.
3 is a tricky solution. You lose time from the installs, but one computer a night and the working hours lost will be negligible. It really depends on how much time your company is willing to invest in this project.
No matter what you decide, best of luck. SSDs may be faster and more durable, but they have their own down-sides...