As a pp says I think it depends what you want it for, I have and pretty much need both. I have a laptop because I'm studying and really need Word and a proper keyboard and mouse for writing long assignments. However, when not studying I use my iPad constantly, I don't open my laptop for anything other than studying unless a website is glitchy on the iPad, I even have an app to send things I need to print to our air printer. So I get the most use out of and prefer the tablet, but I couldn't be without a laptop.
So I just have a HP thing, I can't remember what it was I just gave myself a £350 budget as it isn't worth me spending a lot and bought the best spec I could get for that, it is fast enough for what I need and despite a massive iTunes account (oh I need it for that and writing CDs for the car as well lol) and 10,000+ photos it has plenty more space. Oh and my excel spreadsheets for budgeting, maybe I use it more than I realise! I prefer office on a laptop.
Then I have the iPad 3, I love it, I've never used another tablet so I can't compare but I just love it and it syncs with my iphone, it's like an extension of me.......I like the tablet as it's always on, at hand, fits in my handbag, I use it on my commute I couldn't use a laptop on the tube, and it's my portable tv for around the house ha.
So if it's just internet surfing and not a lot of heavy Microsoft office use I recommend a tablet, and the iPad at that but I know there are some apple haters out there lol.