Fiqh of Music
There is so much music everywhere today, everytime you turn on the TV or the radio, that many people may not realize that there are Islamic regulations about it.
Here is a summary of what I understand to be the Islamic stance on this matter. If I have made any errors, I ask for correction and I seek forgiveness of Allah SWT.
1) Singing or reciting poetry that is not accompanied by any music (i.e., it is just the human voice) is halal as long as the lyrics are Islamic and promote taqwa and faith in Allah SWT and are not about anything haram
2) Singing accompanied by the duff (tambourine or hand drum) is agreed by most scholars to be halal at least on the days of Eid because of the hadith that Abu Bakr (rAa) wanted to forbid a performance of singing with the duff, but the Prophet (sAas) allowed it. Some scholars allow this only on Eid and not any other time
3) Other scholars allow singing accompanied by the duff on other celebratory occasions such as weddings on account of some hadiths that mention entertainment at weddings. This is a recognized difference of opinion among the scholars. Muslims should examine the dalils for both views and follow the one they believe best represents the Sunna of the Prophet (sAas)
4) The singing accompanied by the duff is only halal, whether on Eid or on other occasions, if it is done in a halal setting. That means that women should not sing in front of non-mahram men, people should not listen in mixed gatherings, and there should be no dancing in mixed gatherings nor any kind of alcoholic drinks or other haram behavior
5) A handful of scholars have permitted musical instruments, but the consensus is that musical instruments are haram other than the duff (as described above). When in doubt, go with the consensus
To summarize, if you do listen to singing it should follow these rules:
It should be pretty clear from the above that little or none of the popular music that is available today is Islamically acceptable. It is not just that the lyrics are unIslamic, but also because of the use of musical instruments. There are a growing number of artists who are recording "halal nashids", i.e., songs that follow the above guidelines. There are also some groups that are a bit more flexible; for instance some groups have Islamic lyrics but use musical instruments, while other groups avoid wind and string instruments but do use a variety of percussion instruments not just the duff.
The Islamic Music page has links to various Islamic singing groups. Next to each group I have indicated what type of accompaniment they use. With this, you can avoid the groups whom you do not consider are Islamically correct.
Learning to give up listening to music is very difficult. It is truly a jihad. You may not be able to go "cold turkey".
First, ask Allah SWT to forgive your weakness and your lapses and to help you do what's right.
Second, it may work for you to take it in steps. Probably the first step is to make sure that when you listen to any kind of music it is only in halal settings. Then work to listen only to music that has Islamic lyrics. After that, leave alone the music with the wind and string instruments and stick to percussion. Finally, limit yourself to listening to songs that are accompanied by the duff only. Again, ask Allah SWT to forgive you and to help you.
Frankly, most of the popular music that's available today is pretty trashy. It's definitely not going to encourage you towards taqwa and proper Islamic behavior. Why make things more difficult for yourself by listening to what tempts you towards the wrong? Keep your heart pure and make sure that only good sounds come into your ears, if you can help it.
May Allah SWT guide us all on the straight path.
A survey of the different positions held by the scholars can be found at Music in Islam. A survey of opinions attributed to the founders of the four juristic schools can be found at Opinions of the Four Mujtahid Imams on Music.
The dalils presented by those scholars who say that musical instruments are haram can be found at The Prohibition of Music and Why Music is Haram. The latter strictly limits even the use of the duff. Some scholars argue that even the duff is not allowed and thus all musical instruments are completely haram; see What is the Ruling on the Duff?.
There are also scholars who say that musical instruments are halal as long as the lyrics and the circumstances in which the music is listened to meet the guidelines mentioned above. One of the most prominent of these scholars is Shaykh Yusuf Qaradawi. Read his discussion of music from "The Lawful and the Prohibited in Islam" and a more recent clarification of his position. For additional dalils presented in favor of the legality of musical instruments in halal settings, see An Argument Why Music Should be Considered Halal and On the Prohibition of Music.
Finally, yes, nashids are halal.