Right now, my main setup is a Euro 4 thru a Mesa Bass 400+ into a Mesa Powerhouse 1000 (410 and 15 in one cab). It's a huge sound, but it's not hi fi. It's an old school hard rock sound. The amp can sound incredibly hi fi though. This is not the most portable rig on the planet, but I've done that route, and believe my tone rests in the older style equipment. Another note is the 400+ ONLY has 12 power tubes, lol.
I've also played the same Euro 4 thru an Ampeg SVT 4 Pro with an Eden 410 XLT. This was a great tone, albeit a higher fidelity one. The 4 was great, but doesn't quite have that Ampeg tone that you hear talked about. It is close though. The Eden cab was great, but I think the saying here is they don't build them like they used to.
Lastly, I've also played the Euro 4 thru a Genz Benz Shuttle 9, and a mix of different Avatar cabs (212 + 210, 410 +210, and lastly 410 +212). If you want clear, hi fi tone, something along this route is a good way to go. What this rig won't do is give you enough volume to sit where you want in a mix with a bashing drummer and two loud guitar amps. It will distort on you, and not in a good way. If you want lower volume, warm, but chrstalline type tone, it's a good setup. The 410 and the Shuttle 9 are now my practice setup.
That all being said, I guess, in my own tone travels, I found the light-weight, portable rig just did not deliver what I wanted to hear. It sounds good, don't get me wrong, but it just didn't wow me. As much as I am a drink-the-kool-aid Spector fanboy, I am equally a Mesa Bass amp and cab fanboy. Their cabs are build great and sound phenomenal...I have also heard a 410 and 610 live. I've only played or heard the Bass 400+, but, if I can keep it running, it is the sound in my head. Their other amps have great reputations as well.