Yo Oreo!

I use a Roland SP-808 phrase sampler. It's good in the sense it takes zip disks so I have all my tunes saved on like 6 disks, but it's bad as it can only play 4 samples at one time. Not good when it's all you've got. I havn't had any experience with other samplers but I hear Akai make great ones. Unless your gonna be sampling heavily or performing a lot I wouldn't recommend it.
Yeah, i'm WELL up for getting a Triton or Roland Fantom but in the long run, your probably always better off with a computer. All you really need is the right programs and an $80 (or £) MIDI keyboard. If your like me however and wanna collect some serious gear then go for it.
The baby synth in my photo is an Alesis Micron! It's a miniature combination of Alesis's best synths and has tons of preset sounds. You can create your own but it takes long with only 3 knobs (lots of interface controls to get to know). You'll hear it on most of my tunes, it's definitely a nice synth and v. cheap!
I would recommend getting an all-in-one groove machine like Korg's Electribe series (that's the EMX-1 in the photo). They are good synths and drum sequencers in one cool li'l box. You can do better by buying individually but if your strapped for cash they're a good option i'd say (and wicked fun when you make a tune on the spot )!

Sorry for the longness, just thought you might like some advice.