I've suffered from migraines for over 25 years and Imigran (either 50 or 100mg tablets) is what works best for me. I have never experienced any side effects with sumatriptan. Aspirin and paracetamol-based products are completely useless and don't touch the pain in the slightest. You don't say what type of migraine you have - common or classic (both equally painful). I've more or less outgrown the classic type (probably hormonally triggered in my case) and am stuck with the common type. Depending on bad the nausea and sickness is, you may need to get your GP to prescribe something to combat that.
How much warning of onset do you get? Learning to recognise the onset is the most valuable thing you can do - the sooner you can use the Imigran the less prolonged the attack will be.
A couple of small things that might be of assistance to you: I'm very sensitive to bright sunlight as a trigger so first class sunglasses are essential. Dehydration (even only slightly) is another possible one so if your normal daily water intake isn't very much, make sure you increase it. Sensitivity to certain food groups is worth exploring - the ones with the worst reputation are chocolate, cheese, coffee, red wine/port/brandy - try eliminating all of them and see if it helps.