This! You might also mention who hosts your email, as that might impact your experience as well.
The operating system you are using will impact the clients that are available to you and how well some of those options will perform. I personally use and enjoy KMail - the KDE email client, from within Kontact. This gives me everything I used to enjoy from Thunderbird (and all of the things you list) plus a whole lot more. It is available on Windows, but I'm not sure how well it works there. If you happen to be using Linux and KDE, then there's no reason not to try KMail. Even if you're not using KDE, you could give it a try, but it's going to come with a lot of KDE dependencies.