Me and Rimmel are really having a moment right now. I've been revisiting SunShimmer when an instant tan fix is needed, and pulling out my bottle of Coral Romance nail varnish when I fancy cheerful talons and my bottle of Black Pearl when I'm feeling more glam goth. And for my all my black eyeliner needs, I'm reaching for their Professional Liquid Eyeliner.
It has a fine brush that is probably not going to find favour with eyeliner newbies - you should try something like Ruby & Millie iWriter instead - but it's nowhere near as unwieldy as the brush of Lancome Artliner, which is so skinny that it drives me to distraction. This means it can easily handle everything from a subtle, thin line right along the base of the lashes to a full-on chunky flicked-out cat's eye, and the formula itself is great - it lasts and lasts with zero smudging or flaking.
And with a price tag just shy of €7, it's totally budgettastic too!
Update: this has actually been discontinued and replaced with Glam'Eyes Professional Eyeliner.