Looks like Jojo and me have a lot in common. We both have too many speakers, but can you have too many? What I do is buy them off craigslist, the whole cabinet. Some guys will take a 4, 12's cab made crappy and think putting great speakers in will make a great cabinet. Oh, how wrong. I am gald they do it tho. I bought a 2, 12 with greenbacks last weekend for $50. Guy said he did not like the tone and bought a new cabinet. It is crap to. Anyway, the speakers were not even broke in. Pulled the carpet off the cab and it was built out of MDF.
I couldn't tell you how many speakers I have, but there are many things to consider. I think the first one is closed or open back. I don't care if the specs say for open or closed back, this is not possible for the best sound. Then there is ported or sealed. Partially open or a mixture of woods. The cabinet has just as much influence as the speaker does. Build an oversized cabinet, say 24" x 24" and make it 16" deep closed. Put a 12 inch vintage 30 in it and it will sound completely different than putting it in an open back cab the size of a Tweed Deluxe. Lots of things to consider and it is very expensive just buying something.
There are a few speakers I like in everything, but as mentioned I may have to do some tweaking. My can't go wrong list: Celestion Blue 12, Celestion Gold 10 (the best sounding 10 I have ever heard and paired with a vintage 30 ceramic 10 is just a great combination). Altec 417 is a great speaker all around. JBL 120. I have never used a Weber Alnico that I did not like, but thinking vintage tone here. I am not a fan of Eminence speakers, but that is just opinion. Many love them. Every one I have ever tried came back out and were sold. EVM 12L sounds good with any head I have and are really balanced and the only speaker I pair with the same.
I also mainly play clean and had a friend ask me why I use Vintage 30 since I play clean and it is because they sound great clean. JBL is the only speaker I like in a 15". My least favorite are the new Jensens, old CTS and Utah's. I hate to say it since I am such a fender fan, but I don't care a lot for any Jensen. Some are ok, but I have always found something I like better. I have never warmed up to any of the Warehouse speakers, but I will say they do a great job in high gain territory. I have a few old Black Widows which are great and cheap to get. GM12 Greenbacks to me sound great in a 1, 12, pine cab, birch baffle in an amp with 15 to 20 watts. Hemp is for making rope, not speakers. If you are into death metal it is probably ok.
I do not understand why speakers are called British and American especially since so many are becoming Chinese. I did get one of those Weber Alnico's Slucky used in his radio conversion per his recommendation. Great sounding little speaker. I have one in a modified champ I used at a jam session miked up last weekend. My bass player laughed when I came in with it, but he did not laugh long. They never know what I will be coming with. Man that thing sounded great with my Black Beauty.
And finally I have used HiFi speakers which a lot of Altec and JBL's are with good results. I was reconing some infinities for a guys home theater and before I put them back in his cabinets, I put them in a pine 2, 12 cabinet and they sounded very good I just don't think they would stand up to a lot of distortion. Maybe they would, I just don't know and I did not want to blow a speaker I just fixed.