The first time you load them, no. But if you exit out and reopen them, or hibernate instead of shutting down, then yes, it could help. The real gain will be opening a whole bunch of apps at the same time. Do a simple test, watch your HDD LED, and/or open up the task manager and watch your memory usage. If the HDD blinks a lot and/or all the time, or if the task manager freqently shows you using more than 1024MB, yeah, you could benefit from a gig and a half.
It all depends on what you do. Myself, there are times when I could use another half gig, but I always have two instances of F@H running, and those times are usually when I have about four tabs in IE, a couple MSN conversation windows, and Google Earth running all at the same time. If you do modelling or some new games, yes, more memory will often help, but if not, seems you can usually do just fine with one gig.