Best normal prime lens for a Canon EOS 500D?

seta wrote:

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I understand that the prime lens would be great for portraits (I take a lot portraits of my kids) and also works well in low light. Maybe not a very good option for sightseeing and travel, so I 'll have to complement with my 18-55mm for wide angle photos.

The only 50mm one I found from Canon is an old model: Canon EF 50mm f/1,8 II. But it seems to be discontinued and not very compatible with newer DSLR cameras

The old EF 50 f/1.8 II is fully compatible with the newer DSLR cameras. It has been replaced by the much better constructed EF 50 f/1.8 STM.

The other two alternatives are:

Sigma EX 50mm f/1,4 DG HSM the only 50mm lens I found, but don't know if it is any good.

Plenty good, but some experience AF inconsistencies with the Sigma. YMMV

You should look further, there are lots of other 50s:

Yongnuo EF 50 f/1.8 - a clone of the EF 50 f/1.8 II. Not any better, but cheaper.

Canon EF 50 f/1.4 USM: Aged design, but not a bad lens. Get and use the hood to protect the somewhat fragile extending barrel AF.

Samyang (also sold as Rokinon, Bower, and other brands) 50mm f/1.4 AS IF. Manual focus and aperture, which may be preferable for video use (esp. if "click-less" aperture).

Lensbaby 55mm f/1.6. Don't know anything about it other than it's available for ~$500, is manual focus and manual apterture, but is also a "macro" lens, focusing close enough for 1:2 (1/2 life size) maximum magnification.

Zeiss 50mm f/1.4 ZE Planar T*. High-end manual focus but auto-aperture lens.

Sigma 50 f/1.4 DG HSM Art - improved and more expensive version of the orginal DG HSM

Above $1200 USD there are several even higher-end Zeiss Milvus and Makro-Planar models, and the Canon EF 50 f/1.2L USM.

and finally the $3500 Zeiss 55mm f/1.2 Otus Distagon T*

Canon EF-S 60mm f/2,8 USM Macro I like this the best - it has a slight telephoto feel and has a macro!

Have at it. You may prefer 60mm for portrait focal length, the lens's optical performance is excellent. f/2.8 is 2 stops greater aperture and shallower DOF than your kit 18-55 f/3.5-5.6, but not as thin or "dramatic" as the f/1.8 or f/1.4 alternatives. But then again, sometimes f/1.4 only gets the end of the nose in the plane of focus where f/2.8 can give you the entire face.

Along the same line, there is the Tamron 60mm f/2 Di II Macro.

IMHO, YMMV.