Game music increased the experience indeed, but only when a story is told in my opinion.
Like for example, my favourite games from back in the day (Ocarina of Time, Final Fantasy 8/9) have all amazing music.
And from time to time I still listen to those songs online.
But I think for RuneScape it's different.
Most of the time you'll be doing the same thing, so if you keep hearing the same music it'll get boring.
That's why when I train skills or something I listen to my MP3's on my computer, evil music as you call it.

However, when I'm doing a quest I ALWAYS turn on the RS music.
And there are some great songs in there too.
The last quest is an example of that.
Also, I think the Bandos godsword is only good if you want to kill General Graardor and you don't have enough money to buy an Armadyl godsword or get a chaotic weapon.
For simple things like slayer an abyssal whip is way better.
So a Bandos godsword is not worth buying anymore.
The pick of this week is very related to my interests.
Thank you for sharing.