My new laptop has an i5 processor which gives me the option of a 64bit OS. But as I'm seeing online, I need to create a chroot and have to create a virtual system within the 64bit system to run the 32 bit programs and do a lot of work to do that. However, the main linux install (debian testing) is going to be what I will be using for linux and I'm not sure if its worth the effort for some of the advantages that there are and will be. What does LQ recommend?

(Should I just install another OS (or another debian install) on a small partition and make that 64bit and play around with that while keeping my main install 32bit?)

Do you have > 4G RAM?
Do you do video editing?
Do you do Matlab/Mathematica/other math-intensive things?
Do you do a lot of compiling code?
Do you just want to play with it?

If you answered yes to any of those, you have a good case for going 64-bit. If you didn't, you have no real use case.

I ran 64-bit Debian for a while and had no problems. Java and Flash just worked (Flash has since gotton more complicated since Adobe stopped releasing a 64-bit version). I didn't have to chroot anything though the only 32-bit program I ran intentionally was wine.

I have 4GB ram
no video editing
I don't believe I will be doing anything math-intensive. (I might, but not definitive enough to say yes
I will be compiling code (going for CSE)
I have 50GB free to install another os to play with. And I would rather not have to do any real messing around with my main OS that I don't have to.

What advantage would the 64bit give to compiling code? Just more options, or does 64bit compiled code have more efficiency/stability?

Not much.

No. Well, to be a bit more accurate, I don't know what you mean: do you mean 'is the compiled code more stable' (no) or 'is the development system more stable' (also no, but whether the sixty-four bit system is actually any worse -probably very trivially and unnoticeably worse- depends on whether you are dependant on proprietary apps that can't simply be recompiled by the distributor/end user).

There is a case that 64 bit is less vulnerable to buffer overflow attacks than non-PAE, non-NX systems, but is this what you mean by stability?: buffer overflow attacks aren't exactly common on this platform, andm from this point of view, NX does the same thing.

If you had more than 4G ram, you could make a solid case for it; but then 32 bit PAE code is a bit ugly, but doesn't actually cost much in efficiency.

At 4G, its more of a case of preference; a bit of fiddling versus not having to upgrade in the near future (if that might happen to you). Not the biggest thing for most people.

The tone that I get from your post is that you are desperate to find a big, critical, reason to go, or not go, 64 bit. For many people, in the middle of the memory spectrum, there isn't one.

That irritates me. When I used a 64 bit Linux OS (I think it was Gentoo), I just needed 32bit libraries for 32bit applications ("wine" and others).

The point about compiling code is just related to the math ones: your CPU will get to use more registers and therefore be a little faster. You probably won't notice a difference.