Well, using a 64 bit OS without any *need* for it is foolish (you can browse the web fine with a 32 bit system).
Compare with the "But ... then, why?" in my signature.
Using a 64 bit OS on a machine with 1 Gb of Ram is not respecting the minimum requirements by MS (that have been traditionally a real bare minimum).
Running a 64 bit OS with less than 4 Gb of Ram makes no sense, unless there is a *need* for it, as the only practical advantage of a 64 bit OS is that of being capable (or being licensed) to run more than 4 Gb of RAM.
A 64 bit OS will occupy more space on disk.
There will be more bytes transferred from the mass storage devices to RAM.
The only possible *need* for a 64 bit OS is that of using some "high end" programs that need lots of RAM and fast operations with large numbers, typically graphical programs, very large databases, computational programs and the like that are actually optimized on 64 bit architecture.
This said, if pointertovoid matches the minimum requirement of 2 Gb and senselessly installs a 64 bit Windows 7 on his "browsing the internet only" friend's machine it's perfectly fine :, his friend would not notice any particular difference in his computing experience, though, IF a difference will be noticed it will most probably be that of having the machine less fast/responsive than before.