tonearm cable straight through or plug in

Go straight through. When you count the number of metal-on-metal clip and solder joints eliminated it makes perfect sense, particularly for a low-level signal at the source. The only question is whether you're prepared to rewire a tonearm.

"traight through cable from cartridge to amp - less connections etc... "

You need to have a preamp. Its not optional.

Agree with ZD; I think Dgarretson had read "amp" to be "preamp" in your post. Only qualification is that you could use a standalone phono stage with enough gain and a volume control (like the Aesthetix IO) in lieu of the preamp. But, except in the unusual case of a cartridge that has one (like the Strain Gauge), you need the phono stage (or a preamp with one) for the RIAA equalization it provides.

Straight through is the best sound with a great cable.