Not to revive an old thread....again....but wanted to add my two cents in (raised a JW, drawn my own viewpoints as I've done a lot of research).
There are many religions that don't celebrate certain holidays. I too found it odd that JW's won't celebrate birthdays, but then they go all out and buy their children gifts on anniverseraries - I guess it's to make up for the fact we didn't have any other celebrations. Looking at the history of wedding anniversaries isn't necessarily pagan - it initially started with only celebrating the 25th & 50th back in the middle ages (when most people didn't even reach this time frame as they died younger). Then in the 19th century, people started celebrating them every year and associated a specific type of gift to symbolize the strength of the marriage (cotton, crystal, etc). And of course the 20th century capitalized on the commerce of it all with gifts and cards. While I don't find it wrong to acknowledge ones birthday, the history of the birthday cake does have pagan origins. Birthday wishes/gifts were initially given as a means to ward off evil spirits from a person. Interestingly, name days were created to make the whole event more "Christian" by celebrating the saints instead of the person, which was viewed as a type of self glorification. So there are other reasons to not celebrate in the typical traditional manner one does than just because the focus is on one person for a day or because the two mentioned in the Bible were bad.
Any of the other holidays mentioned - Christmas, Halloween, Easter, etc - do all have pagan origins. This isn't old news as people were aware of this even before the JW's were created. For instance, the mid-17th century saw a ban on Xmas in England. Someone else mentioned the actual wedding - I do find $50k to be excessive for a wedding reception and that it does take away from the sacrament of the event. That is not what JW's are instructed to do, but to each his own. One of my favorite chapters in the Bible is Romans 14 which part of it says "5 One man judges one day as above another; another judges one day the same as all others; let each one be fully convinced in his own mind. 6 The one who observes the day observes it to Jehovah..." So really, we should be doing all things for God's glory, however you personally want to look at "the day". Unfortunately, commercialism and "keeping up with the Jones'" has taken God and the holiness that was once a long time ago associated with such events out and now it's just a gift grab and self-glorification (as I see it anyways).