It totally depends on what you want to use it for. If you want your laptop to fly, and last longer on a battery charge, get the 240. If desktop performance is more important to you, get the 120. Which machine do you spend more time on.
Better answer: Get two 240's and put one in each machine.
as a beta-tester for OCZ I would say to stay away from that older first gen Sandforce controlled drive. The newer controller throttles less.. panic locks you out less.. and recovers quicker at idle and on-the-fly vs the older version.
I usually always say that capacity is your best defense against degradation.. but the newer one will be nealry as fast and keep those speeds for much longer periods of time.
And FYI here.. not sure where you're seeing those prices at.. but the V3 120GB version is $169 after rebate from a few vendors out there right now.