I am a SAHM and I frequently battle with my decision to give up work. I loved my job and after going back just to work the required amount so as not to pay back my maternity pay I really enjoyed having my own identity back again.
I found the decision SO hard, as my peers all seemed to think that you should work. I felt like the only one who was 'giving up' and thats what it was; a failure. The decision was made for me after visiting a few nurseries and seeing some childminders in the park who basically ignored the children(I am not suggesting that all are the same), it just wasn't for me or my DS. So, decision made, I had to deal with it.
Staying at home drives me crazy some days, but on others it is fantastic. Now I have DD too, it seems much more worthwhile, less of a waste somehow.
With regards to working part-time, I think it is a good option. I would love to work part-time and DH do the same, but he claims his company aren't really that flexible and we need his salary more than mine.
In my profession I can also go back fairly easily and I am currently doing other things to add to my CV that will make that more possible.
So, basically, after all that waffle about a subject close to my heart; Stay at home, enjoy DS and if you do need some time out, then work part time. Time flies and we all have many years to continue our careers and rediscover our own identity , but if you waste these precious years with your children now then you cannot get them back