Personally, I think lyrics are subliminally more important than we give them credit for but it's a tough one because we're our own harshest critics.  I often wonder to myself if some of my favourite songs would be my favourite songs had the lyrics been about something completely different, or had they not been able to stir the same emotional response in me.  

I used to write with my best mate who I've always thought was a far better lyricist than I ever will be, but then he thought the same about mine.  The danger is falling in to a trap where you're never happy with your lyrics and convince yourself they can be better even after a hundred re-writes.

As far as favourite songs go, I have to say I'd not have the same set of favourites if their lyrics were different.

Songs are odd in that you can have an instrumental but for it to really have the same power as a song with lyrics it needs to be a journey, emotional or otherwise. It seems that lyrics are a more refined way of describing and creating this journey for the listener and with them more topics can be broached and physical wisdom can be imparted.

I can't remember what I was meaning to get at with that spiel.

Personally I think lyrics are almost always what makes a good song great, though there can be great songs with crap lyirics and great songs with no lyrics. Any good song can become great with great lyrics.

True for me, too. I do know people who listen to songs mostly for the music, but for me it's most often a lyrics-first affair.

Try the lyrics first, or get the theme sorted first. I find it a lot easier to write if I'm writing about something, rather than try and work that out later.  I used to write complete songs without lyrics and then get totally stuck, and then end up writing terrible lyrics to fit the song. I usually steer well clear of books about songwriting but this one is amazing...it talks about brain types and personality types and everything. I'm not exaggerating when I say it completely turned my songwriting around. Give it a go...I recommend it to anyone wanting to improve their work http://www.amazon.co.uk/Songwriters-Idea-Book-Sheila-Davis/dp/0898795192

I agree with Schavuitje about letting whatever is in your head come out.  Normally I will play about with a chord structure and when I find something I like I play it until I get 1 line of the lyrics and build the song from that.

I almost use it as a seed, everything else can make sense from that one line so it happens fairly quickly once I reach this point.  Normally I will finish the song in the next 20 minutes or so after that.

Mat.

I sort of come up with both lyrics and melody at once, though the melody is in my head. The lyrics and melody are basically built around each other. Unfortunately I haven't the skill on guitar to play that melody. I have the skill on bass and drums but not the equipment. Life is just terrible