heheh...everyone is always so curious about that...
first off it really doesn't matter too much what kind of system you are running on unless you are at an extreme end or the other...
a p2 won't be in reality all that much slower then a p4...well openGL it will, but both systems can put out the same quality of work...it when you are getting into animation and production that your system really starts to show it's capabilities..then a p4 will really help a hell of

...incedentally, I started rendering on p-60 with 32 megs of RAM and truespace2

On my website The Maelstrom was born on that system

As were a few of my city scapes

As for helmets...well...lets just say I cheated a lot on those...took me maybe 15 minutes to make...
step 1: create a sphere over the head of your character in a background layer..
step2: use magnet and scale to make it fit the shape of the head a little...
step 3: use extrude and then scale the new polygons to get the major shapes of it to stick out...
step 4: bevel out a few areas to give some detail...( bevel in a couple times to get little indents )
step 5: select the polygons where you want the glass, and extrude them and shrink them and rename those polygons "glass"
step 6, metaform...
step 7, name all th rest of the polysgons with surfaces, the sides "helmet side" the front "helmet front"
step 8: texture
step 9: render
It is literally that easy

Rob