Best leeks to grow throughout the year

Next year, I’d like to grow leeks throughout the year - or, at least, as much as possible. I'm thinking of an early variety and a late variety. After trawling through the Internet, I came across King Richard, for an early harvest, and Toledo, for harvesting late and into the following year. I've always grown Musselburgh in the past and thought I'd like a change.
I’m sure there are many other varieties than the ones I've mentioned so would appreciate hearing what others think, what they have grown, and what they believe are the best.

 

'Elefant' have done pretty well for me even though I've treated them pretty badly. Taste really good too.

 

I usually grow Musselburgh, have tried alternative varieties, but always go back to them.

 

Thanks to all. I was, however, looking for two types - the best to plant early and harvest early and the best to plant late and harvest the next year.

I've always grown Musselburgh so I think that I'll grow those for late and over-wintering into the next year, and King Richard, which, apparently, will mean that I could (I probably wouldn't) harvest in July and onwards until Christmas.