I work with fluids too, mostly during Happy Hour, realflow but not houdini.
Start reading here. I once knew someone who wanted to be a carpenter but did not know the difference between a G clamp, an iron jack and a hacksaw. I told him to learn the tools of his trade first or just buy the furniture he needed. Same for you. If you don't know the tools of your trade, just buy a complete studio or start learning.
I would strongly suggest that you visit with Eric at ADK for a professionally built system. They are probably the must knowledgable NLE builders that I know. For instance I have absolutely no idea what the requirements are for a "vfx compositors system". Now I have been using Premiere since version 1.1 and maybe should know.
I always build my own systems, but I agree with Harm and Bill - it is very easy when you have the necessary knowledge and experience, but without that, near impossible to get a satisfactory system any cheaper than you can buy one from a specialist system builder.
It is not the actual assembly that is difficult; it is the selection of components, and the tuning of the system. For tools you need no more than a selection of small screwdrivers, you have no need to be able to tell a hawk from a handsaw, in Harm's terms.
Most of the threads on this forum are created by people asking for advice on component selection for their proposed new system. I rarely comment because my honest advice would be, if you need this guidance, then don't do it. Buy from a specialist and save yourself a lot of grief, and probably also money, in the end.
not a lot to add. The best would be that you get still access as a freelancer to your old company professional workstation. You could gain some time in checking out your business model first as we speak here from significant HW/SW investments.
For vfx usage think about the largest and fastest 2x 6 core computer, at least 48 GB main storage), a professional OpenGL card from Gforce (e.g. specific support for 3d apps like Maya), 1-3 professional displays, some TB disks with/without raid, etc. To get some grip regarding performance you can run the cinebench at a vendor’s/business friend test workstation (CPU/GL)
PS: Your above mentioned licenses represent a value of approx. 20k$+ (hopefully you got a golden shake hand from your former company or at least you have access to the education editions…) and I assume that you own already a set of in vfx production needed add ons (e.g. video filters, music eq’s, compressors, mastering tools, etc), sample libraries and a good HW monitoring/mixing equipment (Genelec, Yamaha, etc.).
PPS: I run on an i920 (24 GB main storage, GTX 560Ti, 10 TB non raid disks) a full music production (Cubase 6.5, Wavelab 7 and tons of VSTi plugins),a medium level CS5 Master Collection environment (mainly Premiere Pro, After Effects, Photoshop, Adobe Media Encoder and Dreamweaver) and an entry level 3D Cinema 4D app. Next upgrade will be a “real” workstation (either homebuild from a small company nearby or a HP Z600 like computer) as described above and most likely a RAID subsystem.