Confused about RAM

Hi, hoping someone can help. Here is what I'm putting together;

Intel D945G MB (dual core, DDR2 dual channel capable)
Celeron D345J (have this sitting here, going to wait to see what
happens with Pentium D pricing)
Seagate 7200.8 250G HD
Pioneer DVR110 DVD writer (dual layer/16X max wite)
Antec case

I'm really confused about Ram choices; I'm going with 2x512 dual
channel (prob OCZ Gold), but given this choice:

PC4200 533MHz CL-3-3-3-8
PC5400 667MHz CL 4-4-4-8
or would you drop back to DDR and
PC3200 400MHZ CL-2-2-2-5

These are all at roughly the same price point and within the budget.

Which would you go for and why? Also, where would my bottleneck be in
this system as far as data transfer?

To get an idea of my use, I'm not gaming, but may want to occasionally
burn a DVD while listening to music and surfing. I've overclocked in
the past but it's not a big consideration.

Thanks in advance.