Ultimately, it will depend on the capacity of any upgrades, new applications you decide you want,... and the frequency by which you add them.
You don't want to completely fill an SSD, as it needs unused capacity (~10 - 20%, the more the better) for wear leveling. Intel's do have some unused capacity (10% = bare min.) that's invisible to the user, but it's a good idea to leave a little more IMO. Other makes may not, so be aware of it and check. But no matter the brand you get, DON'T fill it all the way.
There are larger capacity drives out there (I'm not sure which is the best though), so do the research if the 160GB Intel's not quite large enough.
Another option could be to add in another unit later for additional applications. You can even RAID them together (you could run into throttling issues if you run an SSD set at the same time as mechancial drives/RAID sets), so a hardware RAID card may be in order. It will depend on the details at the time you decide that this may be an acceptable option.
