Tricky question. First of all, I'm terrible at definite rankings and that kind of stuff anyway...
I like making lists, but they tend to end up being more of a analysis of the selected bunch of things and their relation to one another, rather than stating which is better than the other.
But yeah, I think that in many ways, Maiden is definitely the number one band for me. It's definitely one of those bands whose whole discography really appeals to me and even their weakest outputs are something I find very intriguing and worthwhile digging into from time to time. In a way, it's like supporting a sports team that may have had some weaker seasons, but they're part of the history anyway and even so, might have provided some beautiful memories and individual moments to cherish. Of course, it's easy to give things silver linings retrospectively, especially when one wasn't around to witness it first-hand; that's why many "younger" Maiden fans are undoubtedly very open-minded and intrigued towards things like... Blaze-era, for example.
Another factor, in addition to pure listening time consumed and never-ending love for the whole essence and discography of the band, is probably the pure power of their music, both on record and live. No other band has been able to reach that and of all the bands I love, Maiden definitely has most songs that I personally find as "best" or "most important" to me personally, and so far, majority of the Maiden gigs I've attended (granted, there aren't too many as my first was in 2011 and I couldn't make it to the TBOS run, 2017 London was very close call though...) are among the best concert experiences for me, especially the first shows of 2018 and the 2013 gig.
As for other bands, it's very tricky... Legendary bands like Led Zeppelin, Deep Purple and Pink Floyd have released some of my all-time favourite songs and even albums, but it's often some much more mediocre but important (on a personal level) bands such as Sonata Arctica that I spend a bit more listening time with and embrace their whole discography and the whole
thing around their "
act" very intensively... And when band is active and you can go to their concerts (on a normal circumstances anyway) it naturally adds another layer to the whole "fan experience", when compared to bands whose work I absolutely adore, but can't get the live music experience with. Of course, looking at individual recordings, nothing will ever diminish Stairway to Heaven and it's one fucking godly song that I will surely love to the end of my days. Does that and some other absolutely amazing recordings make Zeppelin top 3, 4 or 5 band for me, above some other act that might not have songs nearly as godly as what Zeppelin has came up with, but has been otherwise very, if not more, important and prominent part of my life? Can't say.
Well, Nightwish is definitely up there too, probably even top 2 or 3. Those concert experiences have all been excellent. Seeing the first show with Floor in Finland (2012), two shows in 2015 (the other being the stadium show in Tampere, which was of course released as part of the Vehicle of Spirit) and Decades show in December 2018... Golden memories.
Metallica is not a band I embrace on such large scale, but some of their songs and albums bear some huge, and still growing significance for me. In a way, Ghost might slide into that category too very soon.
On the solo artist category, I'm a huge fan of Bruce Dickinson's work and The Chemical Wedding might be one of the Top 5 albums for me... And as natural follow-up to the
"member of your favourite band goes solo and you absolutely love it" thing, I found the solo output by Marko Hietala (Nightwish) as one of the best, if not the best, album of 2019 for me. Oh well,
best might be a bit too strong word for it, but on a personal level, it was the most evoking and I still listen to it quite a lot. The Finnish version anyway.
So yeah, behind Maiden there's Nightwish and few legends and then comes a the "guilty-pleasure" thing I have with Sonata Arctica and then... it's hard to say.
Long story short, Iron Maiden is definitely the number one band for me, looking at the personal significance, time consumed, love for the whole discography, concert experiences and pure power of their music.