Persuasion's Painting Outlet

I was planning on visiting 5 european countries, all about 3 days each. Greece, Italy, France also Ireland and England. I was planning on getting a eurail pass but was advised to exclude Ireland as it was better just to get a bus pass there. However, now I'm hearing similar things about Greece and Italy (not to get a bus pass, just not buying a eurail pass . just regular tickets).

Basically, my itinerary is as follows:

Flying into Athens, staying 3 days, then heading for Venice, Italy.
Staying in Venice 3 days, then heading to Paris.
Staying in Paris 3-6 days then heading to Ireland.

The only variation is in the 3-6 days in Paris. Other than that, those are the exact cities I will be staying in and will not be doing much traveling outside of them unless there's something relatively close by.

So, should I get the eurail pass that would include all 3 countries? Or would it just be more economical to buy each ticket respectively?

Thanks!!