Which one is better?

[njanja]

I haven`t gone on holiday this year/summer.
I didn`t go on holiday this year/summer.

[kristinita]

I haven`t gone on holiday this year/summer. is ok only in case when the year or summer is not finished.

I didn`t go on holiday this year/summer.

You may use Past Simple only with summer(this year has a sense that it's not finished and still is going on) because after summer comes autumn and perhaps you're a speaking about your not being on holiday in autumn.

Is everything clear for you? Let me know.

[Avalon]

I haven´t gone...if the year is not finished and there still is a chance of going.
I didn´t go..implies the year has ended and there are no chances of going anymore.

[MrPedantic]

In standard British English, "I haven't been on holiday this year" is more usual than "I haven't gone on holiday this year".

As has been said, it leaves open the possibility of a holiday this year.

MrP

[riverkid]

The summer isn't over yet; today is Thursday, August 24, 2006 and we could use either form for NaE and I suspect for BrE, though the present perfect would, IMHO, be the more likely choice.

As Mr P noted, it would leave the possibility open that a trip could still occur.

Also for NaE, we'd use "a holiday", not usually "holiday" without an indefintie article.

I didn't go on holiday this year/summer.

This too is a possibility. But for either, I think the tendency of speakers would be to add a 'yet' to either style;

I didn't go on a holiday yet this year/this summer.

I haven't been/gone on a holiday yet this year/this summer.

[MrPedantic]

In standard BrE, I would say that only this version would leave the possibility of a holiday open:

1. I haven't been/gone on holiday this year (yet).

While this version (again, in standard BrE) would imply that the possibility was closed:

2. I didn't go on holiday this year.

MrP