New Computer, what should I install?

[markw-FJ05HQ0HCKaWd6l5hS35sQ at public.gmane.org]

After our discussions, I decided to buy an AMD Athlon 64X2 6000 dual core
system. (Barebones + video + 4G RAM) (Oh! Does anyone remember when hard
disks were 4G? But I digress)

I am currently using Kubuntu 6.10 on my desktop, CentOS 4.4 on my servers,
RedHat RHEL 4.4 at work on one machine, Microsoft Windows XP at work on
another machine, Slackware on my robot project, and Kubuntu 6.10 on my
laptop.

(1) Is Linux 64bit "real?" i.e. everything works, or is it 90% of
everything works and some don't?

(2) If I have 64bit Linux, will 32bit apps run?

(3) If I have 64bit Linux, will GCC/G++ target 32bit environments?

(4) Should I just use 32bit until 64bit is real (ignore if #1 is "yes")

What's your personal experience with 64bit Linux?

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