I guess it all depends on your personal definition of moderate. Mine includes 10-15 hours online, no less than 5 conversations with my mother and at least 2-3 emailed links to friends, just to find the PERFECT shirt for my 2nd daughter to wear to her 1st birthday. Seriously obsessed would have applied to my first daughter's, first birthday and the insane search for her dress (no dress for the 2nd one, I am more reasonable now). That entailed the PERFECT dress ordered months in advance from a local woman who (despite my deepest desire to smear her) will remain nameless. That dress arrived so totally different from what was promised that I refused to put it on my daughter (it had puffy sleeves for g-d sakes) and refused to pay for it. Which lead to much last minute insanity and an overnight package from my mother in NY. (thank g-d for overindulgent mothers) It contained no less than five dresses she hoped would fit and be acceptable to a - by then, insane me. I did at the time, try to convince myself that it was not for naught. She looked darling and if I had another girl, she too could wear it for her 1st birthday. I should have been right - their birthday's fall less than 1 month apart. However, I did not anticipate that #2 would outweigh #1 (now almost 4 years old) by many lbs at a year, and therefore the 6-12 month dress would not work.
Back to now. I have done my homework and am so much more the savvy mama than before. I knew the smorgasbord of choices that would be, but a google search away. But ahhhh - there in lies the problem. Who could dive into 24,453 (or so) hits to "birthday t-shirts"? It was overwhelming to say the least. So the aforementioned "moderate obsession" began. I did manage to narrow it down and found several great shares in the process. She will be wearing this www.trendytogs.com/product_p/girlsshirts0300.html.
For the rest of you who might be looking, here are more. Note, that most of these are for birthdays beyond the first as well.
For reasonably priced, but different try www.emiandleo.com
I love the cupcake, ladybugs and the fish for boys.
For the bling chick try www.tutuposh.com
Look under birthday princess boutique.
For sweet and simple try www.snugglebugkids.net
Look under Birthday Items.
For a little humor I LOVED www.blablakids.com/tees.html
These have a farm animal for each year (so one for the 1st birthday and 4 for the 4th) and might be best for boys but are super different!
For those who prefer something more subtle. Something that speaks to your child's ability to show everyone how old they are all by him/herself www.babystyle.com/common/dProductDetail.asp?SIND=1&PMId=21802&cmCL=srch-birthdayt
They also have these for boys and for multiple ages if you search the t-shirt section.
OK, while I could post 1,000 more, those were really my favorites and this is my site after all.