Ia a good amp more important than a good DAC?

Even an inexpensive DAC has very low self-noise, low distortion, and no headroom issues.

Can't say the same thing for a cheap amp.

Amps are big analog circuits with lots of components and connections operating in a hot, high-current environment.

A DAC is just a digital processor (a chip) with a line level output stage.

Thanks a lot for getting involved in my question guys. I am learning a lot but typical of this hobby I seem to have moved one step forwards but two steps back regarding decision making, but I am loving the debate.

Sorry, I am a beginner and never thought to mention my speakers in the question, - they are Magnepan 1.6s and a REL Britannia B3 subwoofer and I use this for music only. I have another pair of speakers that are much more sensitive , or easy to drive - Dali Ikon 7s. These are quite nice and detailed, a "clean" sounding speaker but to me don't have the "big" sound of the Maggies or the "realistic" sound of the Magnepans. They are also pretty "shrill" and sore on the ears as far as the highs go. My musical tastes range from Jazz/Bossanova to rock to electronic, a bit of everything.
Hope that is enough info.

I believe that the source, amp and room are the biggest contributors of sound, which I have recently found out over the past year. If you want to hear this for yourself, go out and listen to some new Rotel electronics and then something tubed or even NAD. There's one for you. Listen to the difference between Rotel and NAD through any speaker. The difference is huge.

Tak the step forward, get the SIM. If you are hooked on Maggies (no reason not to be) you are likely to use SS, and the SIM is a good choice. As has been suggested by most, the amp/speaker combo is critical where is most decent digital sources will do fine for you. The SIM/Maggie sounds like a good long-term combo.

Regarding source first, would you rather have sushi from the best independant Japanese chef in the big city if it had to be delivered to your house in a biker's back pack on a hot August day, or would you rather go to a Legal Seafood, where your fish could be delivered by a short walk from the kitchen to your table?
Jult - I think we agree. Upgrading parts of the system which are not the weakest link will still yield improvements, but just not as much as they should. I'm thinking of my system's cables. I had changed major components over the years, with some good results, but not until I changed the cables did I notice a huge improvement. Now, I can go back and change out some of the components I have not sold yet, and hear bigger differences between them than i oculd before I changed cables. I think the cabe;s were the weak link, and were preventing my other improvements from having the impact they should have.