Counters & Trackers:
The Counter: A counter and tracker in one ^_^, I used this counter on my V-day Page.
BoingDragon's Counters: Very nice animated counters. A lot of options to choose from, I got my heart counter on my index page from that site.
Fast Counter by LinkExchange: A simple little counter :p.
eXTReMe Tracker: The best tracker IMO, it tells ya how many visitors per day, where they're from (countries), how did they get to your page (referrers) etc.
NedStat: A great tracker, tell ya the basic things a tracker would tell ya, but also includes a page view forcast which predicts how many people will be coming to your page (very koO).

Guestbooks:
Dreambook: A nice guestbook service, that's the one I use, but sometimes it's offline -_-!
GuestWorld Guestbook: Another great guestbook service, includes preview and private messages ^_^!

Inspectors:
The SiteInspector: Check your spelling, HTML, popularity, loading time, etc.
Web Site Garage: Another neat inspector ^_^.

Other Stuffs:
Listbot: Get your own mailing list, so you could notify your visitors of updates by mail ^_^. I used it, too. It's on my updates page, join my mailing list will ya ^_-!
SubmitIt!: Submits your site to Yahoo, Hotbot, Altavista, and much, much more ^_^!!!

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