I was about to post the same suggestion... of those you posted, niceday.net is by far the best.
But quality and uniqueness of content and inbound link quality are going to count for a lot more than the domain name. I see many exact match domains way down in the serps because they've ignored these other factors.
Haven't tried keyword reversal in a domain name. Several years back, I did test it in a page title, and I ultimately decided it wasn't useful or desirable. In the phrase I was playing with, it simply wasn't a natural occurrence.
I have used .net TLDs when I haven't been able to get a .com and I've had very good results with them.
Assuming you're targetting the US market then niceday.net is the only and obvious choice.
Today is Sunday or is it DaySun, I would like a beerglass, not a glassbeer, RollingStones or StonesRolling?
Very few people type-in stuff the other way round, yes, it does happen however proportionately at a very low level. What is more important is to get your titlebars using the .net and the description tag and the on-page stuff all to "marry together".
In my view exact domain match in most cases, especially the longer keywords versions, does have unfair advantage. Providing a relevant domain (keyword match) requires much less effort than providing relevant content, and very much depends on luck, earlier opportunity and in many cases the willingness to give up branding for the sake of ranking.
I guess it depends on what you're using it for, but I'd never take out a "niceday.net" when someone else has the niceday.com. Specially if the .com has been around a while. I don't care how many TLDs they spew out, people are always gonna assume .com when they hear an url, and you will end up sending niceday.com a lot of your traffic.
I don't care how many TLDs they spew out, people are always gonna assume .com
Maybe in the US and Canada however outside those regions other extensions are being used extensively.
FWIW over Xmas I changed many of my contact pages and replaced the global .com with my direct .asia and .in addresses and the quality and quantity of enquiries has increased massively and especially so from very busy construction regions.
This may just be my industry but it is very siginificant.