I use Sennheiser HD650 out of my Cowon S9. There's a lot of nonsense in the world of audiophilia about headphone amps, and dedicated DACs, and cables, but I've managed to inform myself and keep myself limited to an extremely comfortable pair of headphones.

One day I'll invest in a speaker set up, but I'll wait until I have the funds and the room to make good use of them.

HydrogenAudio.org is basically my favourite forum for asking questions when you're a naive uninitiated fool interested in audio. On the other hand, head-fi.org is possibly the worst place anyone could be sent if they want to invest in audio

Standard amp. Standard DAC. Standard cables. Great speakers. Great positioning and room acoustics. That seems to be the best audio possible at the moment.