What are your problems with Limewire first of all? You can't search? Is this becasue there is a red circle in the lower left corner. It would mean you're not connected, and, there have been problems with that for other people.
Mac 8.6 huh? Depending on if your system will allow it, I would upgrade to 9.2. I did so on my other Mac (which was also 8.6) and it although it isn't any faster, it's more stable and offers a broader application spectrum to choose of.
As for other types of software. I think for OS 8.6 Limewire is by far your best bet. I've looked around at other programs (before I even stubled accros you) and find they are low budget, slow, and don't offer as many songs to download. Aside from Limewire, there is Myster 5.0 classic. I think the aprroval rating is about 61%. I supposed I'd be apart of that 39%. I didn't like it as much.
I'll find other programs, but nothing really can compare on an OS 8.6 to Limewire. Let's hear about your troubles with Limewire. Fixable Maybe? I hope you don't fall asleep getting through this.