I don't think any of us can really anser for you whether or not you need to "trash" them. That discernment is best left for you to hash out with a trusted spiritual director.
I am always linking to this article, but that's because I think it does such a great job of articulating my sentiments on the subject: by Jimmy Akin*Bad Music*. I highly recommend it as a reasonable approach to secular music.
I love Rush. Some of their lyrics lately have gotten a bit darker lately in light of Neil Peart's personal tragedy (losing both his wife and his daughter). Since he is the principal lyricist, that is obviously going to have an impact.
I'm pretty sure the guys from King's X are Christian.
In any case, I've been listening to hard rock/metal since the 2nd grade. When I had my profound conversion experience, I went through the whole internal dialogue about whether or not I had to pitch the music or if I could keep it.
I think my turning point came when listening to the folk metal band Skyclad's song "Cancer of the Heart." Skyclad is a self-described pagan band (in the truest sense of the word). Some of their songs are quite critical of Christianity, if not downright anti-Christian. But when I listened to this song, I found quite a point of agreement and connection: the song is really a very pointed articulation of Original Sin.
Another song that contributed to this was "Save Our Souls" by Morgana Lefay. They are a somewhat occultish band, but in this song, they seem to be recognize the need for salvation and they are in fact pleading for it.
I began to realize that, though there are many metal acts that are anti-religion, it really stems from their own experience and their own attempt to grapple with the most important questions we face: Who am I? What am I? Why am I here? I respect that sincere struggle moreso than the bands who write exclusively about "luv", which makes up most of pop music's lyrical repertoire.
In the end, I realized that listening to the music was not interfering with my walk with the Lord. I enjoyed the window into another (albeit sometimes darker) worldview, and this only bolstered my faith. I see their struggles and I realize that this is what can happen without the Lord in your life. It encourages me to pray for them earnestly.
I also realized that any of their lyrical "arguments" against Christianity were not very convincing from a logical/philosophical perspective. :)
All this said, I do know people who benefited greatly from purging their CD collection when they had their conversion experience. Certain music (whether rap or metal) brought them back to those dark times in their life when they were far from the Lord. It was something concrete they could do to really make that conscious choice for Christ.
I would encourage you to really take it to prayer. I don't think all Christians are mandated to chuck any and all secular music to the curb. But some are called to do so. Ask God what he is calling you to do.
Have a blessed and merry Christmas!